diff --git a/docs/AIRPORT_REALTIME_SOURCES.md b/docs/AIRPORT_REALTIME_SOURCES.md
index e5fc3654..b21a6340 100644
--- a/docs/AIRPORT_REALTIME_SOURCES.md
+++ b/docs/AIRPORT_REALTIME_SOURCES.md
@@ -21,6 +21,33 @@
 - 仅当当前温度距 DEB 预测最高 ≤3°C 时推送
 - 确认过峰值后自动停止
 
+## 前端市场监控 freshness 契约
+
+后端城市详情接口会在 `current.freshness` / `airport_current.freshness` 返回源感知更新时间信息，前端市场监控不再用统一的 `obs_age_min` 判断所有城市。
+
+关键字段：
+
+```json
+{
+  "source_code": "amos",
+  "source_label": "AMOS",
+  "observed_at": "2026-05-14T11:59:10+00:00",
+  "observed_at_local": "20:59",
+  "native_update_interval_sec": 60,
+  "expected_next_update_at": "2026-05-14T12:00:10+00:00",
+  "freshness_status": "fresh",
+  "freshness_reason": "within_native_fresh_window",
+  "age_sec": 50
+}
+```
+
+前端刷新规则：
+
+- 首次进入市场监控：强制刷新全部城市，绕过 30 分钟前端缓存。
+- 定时轮询：仍以 60s tick 检查，但只刷新已到 `expected_next_update_at`、`delayed`、`stale` 或缺失的城市。
+- BFF 代理：`force_refresh=true` 时使用 `no-store`，避免 Next fetch revalidate 缓存吞掉强刷。
+- 展示：卡片 tooltip 显示源端名称、原生更新间隔和当前 freshness 状态。
+
 ## 消息模板
 
 ```
diff --git a/frontend/app/api/city/[name]/detail/route.ts b/frontend/app/api/city/[name]/detail/route.ts
index b62b2cad..e60e47b4 100644
--- a/frontend/app/api/city/[name]/detail/route.ts
+++ b/frontend/app/api/city/[name]/detail/route.ts
@@ -8,6 +8,7 @@ import {
   buildUpstreamErrorResponse,
 } from "@/lib/api-proxy";
 import { buildCachedJsonResponse } from "@/lib/http-cache";
+import { buildCityDetailProxyCachePolicy } from "@/lib/proxy-cache-policy";
 
 const API_BASE = process.env.POLYWEATHER_API_BASE_URL;
 
@@ -25,6 +26,7 @@ export async function GET(
 
   const { name } = await context.params;
   const forceRefresh = req.nextUrl.searchParams.get("force_refresh") ?? "false";
+  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh, 15);
   const depth = req.nextUrl.searchParams.get("depth");
   const marketSlug = req.nextUrl.searchParams.get("market_slug");
   const targetDate = req.nextUrl.searchParams.get("target_date");
@@ -48,7 +50,9 @@ export async function GET(
     });
     const res = await fetch(url, {
       headers: auth.headers,
-      next: { revalidate: 15 },
+      ...(cachePolicy.fetchMode === "no-store"
+        ? { cache: "no-store" as const }
+        : { next: { revalidate: cachePolicy.revalidateSeconds ?? 15 } }),
     });
     if (!res.ok) {
       const raw = await res.text();
@@ -59,7 +63,7 @@ export async function GET(
     const response = buildCachedJsonResponse(
       req,
       data,
-      "public, max-age=0, s-maxage=15, stale-while-revalidate=45",
+      cachePolicy.responseCacheControl,
     );
     return applyAuthResponseCookies(response, auth.response);
   } catch (error) {
diff --git a/frontend/app/api/city/[name]/route.ts b/frontend/app/api/city/[name]/route.ts
index 205d392b..5fa5e8ca 100644
--- a/frontend/app/api/city/[name]/route.ts
+++ b/frontend/app/api/city/[name]/route.ts
@@ -8,6 +8,7 @@ import {
   buildUpstreamErrorResponse,
 } from "@/lib/api-proxy";
 import { buildCachedJsonResponse } from "@/lib/http-cache";
+import { buildCityDetailProxyCachePolicy } from "@/lib/proxy-cache-policy";
 
 const API_BASE = process.env.POLYWEATHER_API_BASE_URL;
 
@@ -129,6 +130,7 @@ export async function GET(
   const { name } = await context.params;
   const forceRefresh = req.nextUrl.searchParams.get("force_refresh") ?? "false";
   const depth = req.nextUrl.searchParams.get("depth") ?? "panel";
+  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh, 15);
   const url = `${API_BASE}/api/city/${encodeURIComponent(name)}?force_refresh=${forceRefresh}&depth=${encodeURIComponent(depth)}`;
 
   try {
@@ -137,21 +139,27 @@ export async function GET(
     });
     const res = await fetch(url, {
       headers: auth.headers,
-      next: { revalidate: 15 },
+      ...(cachePolicy.fetchMode === "no-store"
+        ? { cache: "no-store" as const }
+        : { next: { revalidate: cachePolicy.revalidateSeconds ?? 15 } }),
     });
     if (!res.ok) {
       const raw = await res.text();
       const summaryUrl = `${API_BASE}/api/city/${encodeURIComponent(name)}/summary?force_refresh=${forceRefresh}`;
       const summaryRes = await fetch(summaryUrl, {
         headers: auth.headers,
-        next: { revalidate: 10 },
+        ...(cachePolicy.fetchMode === "no-store"
+          ? { cache: "no-store" as const }
+          : { next: { revalidate: 10 } }),
       });
       if (summaryRes.ok) {
         const summaryData = await summaryRes.json();
         const response = buildCachedJsonResponse(
           req,
           buildFallbackCityDetail(name, depth, summaryData),
-          "public, max-age=0, s-maxage=10, stale-while-revalidate=30",
+          cachePolicy.fetchMode === "no-store"
+            ? cachePolicy.responseCacheControl
+            : "public, max-age=0, s-maxage=10, stale-while-revalidate=30",
         );
         response.headers.set("X-PolyWeather-Fallback", "summary");
         return applyAuthResponseCookies(response, auth.response);
@@ -164,7 +172,7 @@ export async function GET(
     const response = buildCachedJsonResponse(
       req,
       data,
-      "public, max-age=0, s-maxage=15, stale-while-revalidate=45",
+      cachePolicy.responseCacheControl,
     );
     return applyAuthResponseCookies(response, auth.response);
   } catch (error) {
diff --git a/frontend/app/api/scan/terminal/route.ts b/frontend/app/api/scan/terminal/route.ts
index ed239a25..4af05ca7 100644
--- a/frontend/app/api/scan/terminal/route.ts
+++ b/frontend/app/api/scan/terminal/route.ts
@@ -8,6 +8,7 @@ import {
   buildUpstreamErrorResponse,
 } from "@/lib/api-proxy";
 import { buildCachedJsonResponse } from "@/lib/http-cache";
+import { buildForceRefreshProxyCachePolicy } from "@/lib/proxy-cache-policy";
 
 const API_BASE = process.env.POLYWEATHER_API_BASE_URL;
 const SCAN_TERMINAL_PROXY_TIMEOUT_MS = Number(
@@ -25,6 +26,7 @@ export async function GET(req: NextRequest) {
   }
 
   const params = new URLSearchParams();
+  const forceRefresh = req.nextUrl.searchParams.get("force_refresh") ?? "false";
   for (const key of [
     "scan_mode",
     "min_price",
@@ -42,6 +44,7 @@ export async function GET(req: NextRequest) {
       params.set(key, value);
     }
   }
+  const cachePolicy = buildForceRefreshProxyCachePolicy(forceRefresh, 10);
 
   const url = `${API_BASE}/api/scan/terminal?${params.toString()}`;
 
@@ -55,7 +58,9 @@ export async function GET(req: NextRequest) {
     });
     const res = await fetch(url, {
       headers: auth.headers,
-      next: { revalidate: 10 },
+      ...(cachePolicy.fetchMode === "no-store"
+        ? { cache: "no-store" as const }
+        : { next: { revalidate: cachePolicy.revalidateSeconds ?? 10 } }),
       signal: controller.signal,
     });
     if (!res.ok) {
@@ -67,7 +72,7 @@ export async function GET(req: NextRequest) {
     const response = buildCachedJsonResponse(
       req,
       data,
-      "public, max-age=0, s-maxage=10, stale-while-revalidate=30",
+      cachePolicy.responseCacheControl,
     );
     return applyAuthResponseCookies(response, auth.response);
   } catch (error) {
diff --git a/frontend/components/dashboard/monitoring/MonitorPanel.tsx b/frontend/components/dashboard/monitoring/MonitorPanel.tsx
index b4c541e8..b0a42e9e 100644
--- a/frontend/components/dashboard/monitoring/MonitorPanel.tsx
+++ b/frontend/components/dashboard/monitoring/MonitorPanel.tsx
@@ -1,9 +1,20 @@
 "use client";
 
 import { useMemo, useState, useEffect, useRef, useCallback } from "react";
-import { useDashboardStore } from "@/hooks/useDashboardStore";
+import { useCityDetails, useDashboardActions } from "@/hooks/useDashboardStore";
 import { useI18n } from "@/hooks/useI18n";
-import type { CityDetail } from "@/lib/dashboard-types";
+import type { CityDetail, ObservationFreshness } from "@/lib/dashboard-types";
+import {
+  getMonitorFreshnessLevel,
+  getObservationFreshness,
+  shouldRefreshMonitorCity,
+  type MonitorFreshnessLevel,
+} from "@/lib/source-freshness";
+import {
+  getMonitorRefreshRequest,
+  MONITOR_REFRESH_INTERVAL_MS,
+  type MonitorRefreshTrigger,
+} from "./monitor-refresh-policy";
 
 /* ── Constants ───────────────────────────────────────────────── */
 const MONITOR_KEYS = [
@@ -14,33 +25,42 @@ const MONITOR_KEYS = [
 ] as const;
 
 type MonitorKey = (typeof MONITOR_KEYS)[number];
+type MonitorRefreshRequest = ReturnType<typeof getMonitorRefreshRequest>;
 
 const CONCURRENCY = 6;
-const REFRESH_INTERVAL_MS = 60_000;
 
 /* ── Helpers ─────────────────────────────────────────────────── */
 type Lang = { isEn: boolean };
 function t(en: string, zh: string, { isEn }: Lang) { return isEn ? en : zh; }
 
-type Freshness = "fresh" | "aging" | "stale" | "unknown";
+type Freshness = MonitorFreshnessLevel;
 
-function freshnessLevel(ageMin: number | null | undefined): Freshness {
-  if (ageMin == null) return "unknown";
-  if (ageMin < 20) return "fresh";
-  if (ageMin < 45) return "aging";
-  return "stale";
-}
-
-function freshnessDotTitle(level: Freshness, ageMin: number | null | undefined, isEn: boolean): string {
+function freshnessDotTitle(
+  level: Freshness,
+  ageMin: number | null | undefined,
+  isEn: boolean,
+  freshness?: ObservationFreshness | null,
+): string {
   const age = ageMin != null ? (isEn ? `${ageMin} min ago` : `${ageMin} 分钟前`) : "--";
+  const source = freshness?.source_label ? `${freshness.source_label} · ` : "";
+  const cadence =
+    freshness?.native_update_interval_sec != null
+      ? Math.round(freshness.native_update_interval_sec / 60)
+      : null;
+  const cadenceText =
+    cadence != null
+      ? isEn
+        ? ` · native cadence ${cadence} min`
+        : ` · 源端约 ${cadence} 分钟更新`
+      : "";
   if (isEn) {
-    return level === "fresh" ? `Fresh · ${age}` :
-           level === "aging" ? `Aging · ${age}` :
-           level === "stale" ? `Stale · ${age}` : "Unknown age";
+    return level === "fresh" ? `${source}Fresh · ${age}${cadenceText}` :
+           level === "aging" ? `${source}Waiting / aging · ${age}${cadenceText}` :
+           level === "stale" ? `${source}Stale · ${age}${cadenceText}` : `${source}Unknown age${cadenceText}`;
   }
-  return level === "fresh" ? `数据新鲜 · ${age}` :
-         level === "aging" ? `数据变旧 · ${age}` :
-         level === "stale" ? `数据陈旧 · ${age}` : "更新时间未知";
+  return level === "fresh" ? `${source}数据新鲜 · ${age}${cadenceText}` :
+         level === "aging" ? `${source}等待源端更新 / 数据变旧 · ${age}${cadenceText}` :
+         level === "stale" ? `${source}数据陈旧 · ${age}${cadenceText}` : `${source}更新时间未知${cadenceText}`;
 }
 
 /* ── Audio alert (Web Audio API, no external file needed) ────── */
@@ -147,7 +167,13 @@ function airportLabel(key: string, isEn: boolean) {
  */
 const HKO_OBS_CITIES = new Set<MonitorKey>(["hong kong", "lau fau shan"]);
 
-function obsSourceLabel(key: MonitorKey, isEn: boolean): string {
+function obsSourceLabel(
+  key: MonitorKey,
+  isEn: boolean,
+  freshness?: ObservationFreshness | null,
+): string {
+  const sourceLabel = String(freshness?.source_label || "").trim();
+  if (sourceLabel) return sourceLabel;
   if (HKO_OBS_CITIES.has(key)) return isEn ? "HKO Obs" : "天文台观测";
   return isEn ? "Airport METAR" : "机场报文";
 }
@@ -181,14 +207,19 @@ export default function MonitorPanel({
 }: {
   onCityClick?: (cityName: string) => void;
 }) {
-  const store = useDashboardStore();
+  const { ensureCityDetail } = useDashboardActions();
   const { locale } = useI18n();
   const isEn = locale === "en-US";
   const lang: Lang = { isEn };
 
-  const details = store.cityDetailsByName;
+  const { cityDetailsByName: details } = useCityDetails();
   const detailsRef = useRef(details);
   detailsRef.current = details;
+  const ensureCityDetailRef = useRef(ensureCityDetail);
+
+  useEffect(() => {
+    ensureCityDetailRef.current = ensureCityDetail;
+  }, [ensureCityDetail]);
 
   const [time, setTime] = useState("");
   const [fetchingKeys, setFetchingKeys] = useState<ReadonlySet<string>>(new Set());
@@ -238,10 +269,10 @@ export default function MonitorPanel({
 
   /* Per-city fetch with loading-key tracking */
   const fetchCity = useCallback(
-    async (key: MonitorKey, force: boolean) => {
+    async (key: MonitorKey, request: MonitorRefreshRequest) => {
       setFetchingKeys((prev) => new Set([...prev, key]));
       try {
-        await store.ensureCityDetail(key, force, "panel");
+        await ensureCityDetailRef.current(key, request.force, request.depth);
       } catch {
         /* individual city errors are shown as "--" in the card */
       } finally {
@@ -252,30 +283,52 @@ export default function MonitorPanel({
         });
       }
     },
-    [store.ensureCityDetail],
+    [],
   );
 
   /* Refresh all cities, sorted by staleness (most stale first). */
   const refreshAll = useCallback(
-    async (force: boolean) => {
+    async (trigger: MonitorRefreshTrigger) => {
       if (globalFetchingRef.current) return;
       globalFetchingRef.current = true;
+      const request = getMonitorRefreshRequest(trigger);
 
-      /* Sort keys: cities with no data first, then by obs_age_min descending */
-      const sorted = [...MONITOR_KEYS].sort((a, b) => {
+      const now = new Date();
+      /* Sort keys: cities with no data first, then by source-aware freshness/staleness. */
+      const dueKeys = [...MONITOR_KEYS].filter((key) =>
+        shouldRefreshMonitorCity({
+          detail: detailsRef.current[key],
+          now,
+          trigger,
+        }),
+      );
+
+      const sorted = dueKeys.sort((a, b) => {
         const d = detailsRef.current;
-        const ageA = d[a]?.airport_current?.obs_age_min ?? Infinity;
-        const ageB = d[b]?.airport_current?.obs_age_min ?? Infinity;
+        const freshA = getObservationFreshness(d[a]);
+        const freshB = getObservationFreshness(d[b]);
+        const ageA =
+          freshA?.age_sec != null
+            ? freshA.age_sec / 60
+            : d[a]?.airport_current?.obs_age_min ?? Infinity;
+        const ageB =
+          freshB?.age_sec != null
+            ? freshB.age_sec / 60
+            : d[b]?.airport_current?.obs_age_min ?? Infinity;
         return ageB - ageA; // stale first
       });
 
       const queue = sorted as MonitorKey[];
+      if (queue.length === 0) {
+        globalFetchingRef.current = false;
+        return;
+      }
       const workers = Array.from({ length: CONCURRENCY }, async () => {
         while (queue.length > 0) {
           if (cancelledRef.current) return;
           const key = queue.shift();
           if (!key) break;
-          await fetchCity(key, force);
+          await fetchCity(key, request);
         }
       });
       await Promise.allSettled(workers);
@@ -290,10 +343,10 @@ export default function MonitorPanel({
 
   useEffect(() => {
     cancelledRef.current = false;
-    void refreshAll(false);
+    void refreshAll("initial");
     const timer = setInterval(() => {
-      if (!document.hidden) void refreshAll(true);
-    }, REFRESH_INTERVAL_MS);
+      if (!document.hidden) void refreshAll("interval");
+    }, MONITOR_REFRESH_INTERVAL_MS);
     return () => {
       cancelledRef.current = true;
       clearInterval(timer);
@@ -427,9 +480,17 @@ export default function MonitorPanel({
           const cur = ac?.temp ?? detail.current?.temp ?? null;
           const max = resolveMaxSoFar(detail, key);          // HKO cities fall back to current.max_so_far
           const mtt = ac?.max_temp_time ?? detail.current?.max_temp_time ?? null;
-          const obs = ac?.obs_time ?? detail.local_time ?? "";
-          const age = ac?.obs_age_min ?? null;
-          const freshness = freshnessLevel(age);
+          const freshnessInfo = getObservationFreshness(detail);
+          const obs =
+            ac?.obs_time ??
+            freshnessInfo?.observed_at_local ??
+            detail.current?.obs_time ??
+            detail.local_time ??
+            "";
+          const age =
+            ac?.obs_age_min ??
+            (freshnessInfo?.age_sec != null ? Math.round(freshnessInfo.age_sec / 60) : null);
+          const freshness = getMonitorFreshnessLevel(freshnessInfo, age);
           const tempSymbol = detail.temp_symbol || "°C";  // °F for US cities
           const newHigh = cur != null && max != null && cur >= max + 0.3;
           const warm = !newHigh && cur != null && cur >= 30;
@@ -462,7 +523,7 @@ export default function MonitorPanel({
                 <span className="monitor-airport-name">/ {airportLabel(key, isEn)}</span>
                 <FreshnessDot
                   level={freshness}
-                  title={freshnessDotTitle(freshness, age, isEn)}
+                  title={freshnessDotTitle(freshness, age, isEn, freshnessInfo)}
                 />
                 {newHigh && (
                   <span className="monitor-new-high-badge">
@@ -502,7 +563,7 @@ export default function MonitorPanel({
                 </div>
                 <div className="monitor-obs-row">
                   <span className="monitor-stat-label">
-                    {obsSourceLabel(key, isEn)}
+                    {obsSourceLabel(key, isEn, freshnessInfo)}
                   </span>
                   <span className={`monitor-obs-age ${freshness}`}>
                     {age != null ? (
diff --git a/frontend/components/dashboard/monitoring/monitor-refresh-policy.ts b/frontend/components/dashboard/monitoring/monitor-refresh-policy.ts
new file mode 100644
index 00000000..339adf70
--- /dev/null
+++ b/frontend/components/dashboard/monitoring/monitor-refresh-policy.ts
@@ -0,0 +1,11 @@
+export const MONITOR_CITY_DETAIL_DEPTH = "panel" as const;
+export const MONITOR_REFRESH_INTERVAL_MS = 60_000;
+
+export type MonitorRefreshTrigger = "initial" | "interval";
+
+export function getMonitorRefreshRequest(_trigger: MonitorRefreshTrigger) {
+  return {
+    depth: MONITOR_CITY_DETAIL_DEPTH,
+    force: true,
+  };
+}
diff --git a/frontend/components/dashboard/scan-terminal/__tests__/httpError.test.ts b/frontend/components/dashboard/scan-terminal/__tests__/httpError.test.ts
new file mode 100644
index 00000000..19d50c5f
--- /dev/null
+++ b/frontend/components/dashboard/scan-terminal/__tests__/httpError.test.ts
@@ -0,0 +1,18 @@
+import assert from "node:assert/strict";
+import { formatHttpErrorMessage } from "@/lib/http-error";
+
+export function runTests() {
+  assert.equal(formatHttpErrorMessage(502), "HTTP 502");
+  assert.equal(
+    formatHttpErrorMessage(403, "Forbidden", '{"detail":"missing entitlement"}'),
+    "HTTP 403 Forbidden: missing entitlement",
+  );
+  assert.equal(
+    formatHttpErrorMessage(500, null, '{"error":{"code":"boom"}}'),
+    'HTTP 500: {"code":"boom"}',
+  );
+  assert.equal(
+    formatHttpErrorMessage(504, "Gateway Timeout", " upstream timed out\n"),
+    "HTTP 504 Gateway Timeout: upstream timed out",
+  );
+}
diff --git a/frontend/components/dashboard/scan-terminal/__tests__/monitorRefreshPolicy.test.ts b/frontend/components/dashboard/scan-terminal/__tests__/monitorRefreshPolicy.test.ts
new file mode 100644
index 00000000..2bc55173
--- /dev/null
+++ b/frontend/components/dashboard/scan-terminal/__tests__/monitorRefreshPolicy.test.ts
@@ -0,0 +1,19 @@
+import assert from "node:assert/strict";
+import {
+  getMonitorRefreshRequest,
+  MONITOR_CITY_DETAIL_DEPTH,
+} from "@/components/dashboard/monitoring/monitor-refresh-policy";
+
+export function runTests() {
+  const initial = getMonitorRefreshRequest("initial");
+  assert.equal(
+    initial.force,
+    true,
+    "monitor initial load must force refresh instead of showing 30-minute session cache",
+  );
+  assert.equal(initial.depth, MONITOR_CITY_DETAIL_DEPTH);
+
+  const interval = getMonitorRefreshRequest("interval");
+  assert.equal(interval.force, true);
+  assert.equal(interval.depth, MONITOR_CITY_DETAIL_DEPTH);
+}
diff --git a/frontend/components/dashboard/scan-terminal/__tests__/proxyCachePolicy.test.ts b/frontend/components/dashboard/scan-terminal/__tests__/proxyCachePolicy.test.ts
new file mode 100644
index 00000000..9761d1c2
--- /dev/null
+++ b/frontend/components/dashboard/scan-terminal/__tests__/proxyCachePolicy.test.ts
@@ -0,0 +1,25 @@
+import assert from "node:assert/strict";
+import {
+  buildCityDetailProxyCachePolicy,
+  buildForceRefreshProxyCachePolicy,
+  isForceRefreshValue,
+} from "@/lib/proxy-cache-policy";
+
+export function runTests() {
+  assert.equal(isForceRefreshValue("true"), true);
+  assert.equal(isForceRefreshValue("false"), false);
+  assert.equal(isForceRefreshValue(null), false);
+
+  const forced = buildCityDetailProxyCachePolicy("true");
+  assert.equal(forced.fetchMode, "no-store");
+  assert.match(forced.responseCacheControl, /no-store/);
+  assert.equal(forced.revalidateSeconds, undefined);
+
+  const cached = buildCityDetailProxyCachePolicy("false", 15);
+  assert.equal(cached.fetchMode, "revalidate");
+  assert.equal(cached.revalidateSeconds, 15);
+  assert.match(cached.responseCacheControl, /s-maxage=15/);
+
+  const scanForced = buildForceRefreshProxyCachePolicy("true", 10);
+  assert.equal(scanForced.fetchMode, "no-store");
+}
diff --git a/frontend/components/dashboard/scan-terminal/__tests__/sourceFreshness.test.ts b/frontend/components/dashboard/scan-terminal/__tests__/sourceFreshness.test.ts
new file mode 100644
index 00000000..0cf4dc83
--- /dev/null
+++ b/frontend/components/dashboard/scan-terminal/__tests__/sourceFreshness.test.ts
@@ -0,0 +1,92 @@
+import assert from "node:assert/strict";
+import {
+  buildObservationFreshness,
+  getMonitorFreshnessLevel,
+  getMonitorRefreshCadenceMs,
+  getObservationSourceProfile,
+  shouldRefreshMonitorCity,
+} from "@/lib/source-freshness";
+import type { CityDetail } from "@/lib/dashboard-types";
+
+function detail(extra: Partial<CityDetail>): CityDetail {
+  return {
+    current: { temp: null },
+    display_name: "Test",
+    lat: 0,
+    local_date: "2026-05-14",
+    local_time: "12:00",
+    lon: 0,
+    name: "test",
+    risk: { level: "low" },
+    temp_symbol: "°C",
+    ...extra,
+  } as CityDetail;
+}
+
+export function runTests() {
+  const now = new Date("2026-05-14T12:00:00Z");
+
+  assert.equal(getObservationSourceProfile("amos").nativeUpdateIntervalSec, 60);
+  assert.equal(getObservationSourceProfile("metar").nativeUpdateIntervalSec, 900);
+
+  const amosFresh = buildObservationFreshness({
+    now,
+    observedAt: "2026-05-14T11:59:10Z",
+    sourceCode: "amos",
+    sourceLabel: "AMOS",
+  });
+  assert.equal(amosFresh.freshness_status, "fresh");
+  assert.equal(getMonitorFreshnessLevel(amosFresh, null), "fresh");
+  assert.equal(
+    shouldRefreshMonitorCity({
+      detail: detail({ airport_current: { freshness: amosFresh, obs_time: "11:59", temp: 20 } }),
+      now,
+      trigger: "interval",
+    }),
+    false,
+  );
+
+  const metarStillExpected = buildObservationFreshness({
+    now,
+    observedAt: "2026-05-14T11:48:00Z",
+    sourceCode: "metar",
+    sourceLabel: "METAR",
+  });
+  assert.equal(metarStillExpected.freshness_status, "expected_wait");
+  assert.equal(getMonitorFreshnessLevel(metarStillExpected, null), "aging");
+
+  const metarOld = buildObservationFreshness({
+    now,
+    observedAt: "2026-05-14T10:50:00Z",
+    sourceCode: "metar",
+    sourceLabel: "METAR",
+  });
+  assert.equal(metarOld.freshness_status, "stale");
+  assert.equal(getMonitorFreshnessLevel(metarOld, null), "stale");
+  assert.equal(
+    shouldRefreshMonitorCity({
+      detail: detail({ airport_current: { freshness: metarOld, obs_time: "10:50", temp: 20 } }),
+      now,
+      trigger: "interval",
+    }),
+    true,
+  );
+
+  assert.equal(
+    shouldRefreshMonitorCity({ detail: undefined, now, trigger: "interval" }),
+    true,
+    "missing city detail should always be fetched",
+  );
+  assert.equal(
+    shouldRefreshMonitorCity({
+      detail: detail({ airport_current: { obs_age_min: 5, obs_time: "11:55", temp: 20 } }),
+      now,
+      trigger: "interval",
+    }),
+    false,
+    "legacy METAR age under native cadence should not be force-refreshed every minute",
+  );
+
+  assert.equal(getMonitorRefreshCadenceMs(["amos", "metar"]), 60_000);
+  assert.equal(getMonitorRefreshCadenceMs(["metar"]), 300_000);
+}
diff --git a/frontend/hooks/useDashboardStore.tsx b/frontend/hooks/useDashboardStore.tsx
index 2e7e9606..4cf26d76 100644
--- a/frontend/hooks/useDashboardStore.tsx
+++ b/frontend/hooks/useDashboardStore.tsx
@@ -74,6 +74,10 @@ interface DashboardStoreValue extends DashboardState {
 }
 
 const DashboardStoreContext = createContext<DashboardStoreValue | null>(null);
+const DashboardActionsContext = createContext<Pick<
+  DashboardStoreValue,
+  "ensureCityDetail"
+> | null>(null);
 const CityDetailsContext = createContext<{
   cityDetailsByName: Record<string, CityDetail>;
   cityDetailMetaByName: Record<string, { cachedAt: number; revision: string }>;
@@ -1550,12 +1554,24 @@ export function DashboardStoreProvider({
     () => ({ cityDetailsByName, cityDetailMetaByName, citySummariesByName, loadingState }),
     [cityDetailsByName, cityDetailMetaByName, citySummariesByName, loadingState],
   );
+  const latestEnsureCityDetailRef = useRef(ensureCityDetail);
+  useEffect(() => {
+    latestEnsureCityDetailRef.current = ensureCityDetail;
+  }, [ensureCityDetail]);
+  const dashboardActionsValue = useMemo<Pick<DashboardStoreValue, "ensureCityDetail">>(
+    () => ({
+      ensureCityDetail: (...args) => latestEnsureCityDetailRef.current(...args),
+    }),
+    [],
+  );
 
   return (
     <DashboardStoreContext.Provider value={value}>
-      <CityDetailsContext.Provider value={cityDetailsValue}>
-        {children}
-      </CityDetailsContext.Provider>
+      <DashboardActionsContext.Provider value={dashboardActionsValue}>
+        <CityDetailsContext.Provider value={cityDetailsValue}>
+          {children}
+        </CityDetailsContext.Provider>
+      </DashboardActionsContext.Provider>
     </DashboardStoreContext.Provider>
   );
 }
@@ -1580,6 +1596,16 @@ export function useCityDetails() {
   return context;
 }
 
+export function useDashboardActions() {
+  const context = useContext(DashboardActionsContext);
+  if (!context) {
+    throw new Error(
+      "useDashboardActions must be used within DashboardStoreProvider",
+    );
+  }
+  return context;
+}
+
 export function useCityData(name?: string | null) {
   const store = useDashboardStore();
   const key = name || store.selectedCity;
diff --git a/frontend/lib/dashboard-client.ts b/frontend/lib/dashboard-client.ts
index ff942166..3b542e8a 100644
--- a/frontend/lib/dashboard-client.ts
+++ b/frontend/lib/dashboard-client.ts
@@ -13,6 +13,7 @@ import {
   buildBrowserBackendHeaders,
   fetchBackendApi,
 } from "@/lib/backend-api";
+import { formatHttpErrorMessage } from "@/lib/http-error";
 
 const CACHE_KEY = "polyWeather_v1";
 const CACHE_TTL_MS = 30 * 60 * 1000;
@@ -54,7 +55,10 @@ function normalizeDetailDepth(depth?: "panel" | "market" | "nearby" | "full") {
   return "panel";
 }
 
-async function fetchJson<T>(url: string, options?: { timeoutMs?: number }): Promise<T> {
+async function fetchJson<T>(
+  url: string,
+  options?: { cache?: RequestCache; timeoutMs?: number },
+): Promise<T> {
   const timeoutMs = options?.timeoutMs;
   const controller = timeoutMs ? new AbortController() : null;
   const timeoutId = controller
@@ -68,7 +72,7 @@ async function fetchJson<T>(url: string, options?: { timeoutMs?: number }): Prom
   try {
     response = await fetchBackendApi(url, {
       headers,
-      cache: "default",
+      cache: options?.cache ?? "default",
       signal: controller?.signal,
     });
   } catch (error) {
@@ -83,7 +87,10 @@ async function fetchJson<T>(url: string, options?: { timeoutMs?: number }): Prom
   }
 
   if (!response.ok) {
-    throw new Error(`HTTP ${response.status}`);
+    const body = await response.text().catch(() => "");
+    throw new Error(
+      formatHttpErrorMessage(response.status, response.statusText, body),
+    );
   }
 
   return response.json() as Promise<T>;
@@ -253,6 +260,7 @@ export const dashboardClient = {
 
     const request = fetchJson<CitySummary>(
       `/api/city/${normalizeCityName(cityName)}/summary?force_refresh=${force}`,
+      force ? { cache: "no-store" } : undefined,
     ).finally(() => {
       pendingCitySummaryRequests.delete(requestKey);
     });
@@ -292,7 +300,7 @@ export const dashboardClient = {
     });
     return fetchJson<CityDetail>(
       `/api/city/${normalizeCityName(cityName)}?${params.toString()}`,
-      { timeoutMs: CITY_DETAIL_CLIENT_TIMEOUT_MS },
+      { cache: "no-store", timeoutMs: CITY_DETAIL_CLIENT_TIMEOUT_MS },
     );
   },
 
@@ -340,6 +348,7 @@ export const dashboardClient = {
     const request = (async () => {
       const payload = await fetchJson<MarketScanPayload>(
         `/api/city/${normalizeCityName(cityName)}/market-scan?${params.toString()}`,
+        force ? { cache: "no-store" } : undefined,
       );
       if (!force && options?.marketSlug && isStaleMarketSlugResponse(payload)) {
         const fallbackParams = new URLSearchParams({
@@ -389,7 +398,10 @@ export const dashboardClient = {
     }
     const request = fetchJson<ScanTerminalResponse>(
       `/api/scan/terminal?${params.toString()}`,
-      { timeoutMs: SCAN_TERMINAL_CLIENT_TIMEOUT_MS },
+      {
+        cache: force ? "no-store" : "default",
+        timeoutMs: SCAN_TERMINAL_CLIENT_TIMEOUT_MS,
+      },
     ).finally(() => {
       pendingScanTerminalRequests.delete(requestKey);
     });
@@ -426,7 +438,10 @@ export const dashboardClient = {
     }))
       .then(async (response) => {
         if (!response.ok) {
-          throw new Error(`HTTP ${response.status}`);
+          const body = await response.text().catch(() => "");
+          throw new Error(
+            formatHttpErrorMessage(response.status, response.statusText, body),
+          );
         }
         return response.json() as Promise<ScanTerminalResponse>;
       })
diff --git a/frontend/lib/dashboard-types.ts b/frontend/lib/dashboard-types.ts
index a6b0418b..ab6fd73b 100644
--- a/frontend/lib/dashboard-types.ts
+++ b/frontend/lib/dashboard-types.ts
@@ -53,6 +53,27 @@ export interface CloudLayer {
   base: number | null;
 }
 
+export interface ObservationFreshness {
+  source_code?: string | null;
+  source_label?: string | null;
+  observed_at?: string | null;
+  observed_at_local?: string | null;
+  ingested_at?: string | null;
+  native_update_interval_sec?: number | null;
+  expected_next_update_at?: string | null;
+  freshness_status?:
+    | "fresh"
+    | "expected_wait"
+    | "delayed"
+    | "stale"
+    | "offline"
+    | "unknown"
+    | string
+    | null;
+  freshness_reason?: string | null;
+  age_sec?: number | null;
+}
+
 export interface CurrentConditions {
   temp: number | null;
   max_so_far: number | null;
@@ -76,6 +97,8 @@ export interface CurrentConditions {
   report_time?: string | null;
   receipt_time?: string | null;
   obs_time_epoch?: number | null;
+  source_code?: string | null;
+  freshness?: ObservationFreshness | null;
   dewpoint?: number | null;
 }
 
@@ -95,6 +118,7 @@ export interface AirportCurrentConditions {
   visibility_mi?: number | null;
   wx_desc?: string | null;
   raw_metar?: string | null;
+  source_code?: string | null;
   source_label?: string | null;
   station_code?: string | null;
   station_label?: string | null;
@@ -105,6 +129,7 @@ export interface AirportCurrentConditions {
   pressure_hpa?: number | null;
   last_observation_local_date?: string | null;
   current_local_date?: string | null;
+  freshness?: ObservationFreshness | null;
 }
 
 export interface NearbyStation {
diff --git a/frontend/lib/http-error.ts b/frontend/lib/http-error.ts
new file mode 100644
index 00000000..81fcc1e5
--- /dev/null
+++ b/frontend/lib/http-error.ts
@@ -0,0 +1,29 @@
+export function formatHttpErrorMessage(
+  status: number,
+  statusText?: string | null,
+  body?: string | null,
+) {
+  const base = `HTTP ${status}${statusText ? ` ${statusText}` : ""}`;
+  const rawBody = String(body || "").trim();
+  if (!rawBody) return base;
+
+  let detail = rawBody;
+  try {
+    const parsed = JSON.parse(rawBody) as {
+      detail?: unknown;
+      error?: unknown;
+      message?: unknown;
+    };
+    const value = parsed.detail ?? parsed.error ?? parsed.message;
+    if (value != null) {
+      detail =
+        typeof value === "string" ? value : JSON.stringify(value);
+    }
+  } catch {
+    // keep raw body
+  }
+
+  const normalized = detail.replace(/\s+/g, " ").trim();
+  if (!normalized) return base;
+  return `${base}: ${normalized.slice(0, 300)}`;
+}
diff --git a/frontend/lib/proxy-cache-policy.ts b/frontend/lib/proxy-cache-policy.ts
new file mode 100644
index 00000000..c3f91185
--- /dev/null
+++ b/frontend/lib/proxy-cache-policy.ts
@@ -0,0 +1,31 @@
+export type ProxyCachePolicy = {
+  fetchMode: "no-store" | "revalidate";
+  responseCacheControl: string;
+  revalidateSeconds?: number;
+};
+
+export function isForceRefreshValue(value: string | null | undefined) {
+  return String(value || "").trim().toLowerCase() === "true";
+}
+
+export function buildForceRefreshProxyCachePolicy(
+  forceRefresh: string | null | undefined,
+  revalidateSeconds = 15,
+): ProxyCachePolicy {
+  if (isForceRefreshValue(forceRefresh)) {
+    return {
+      fetchMode: "no-store",
+      responseCacheControl: "no-store, max-age=0",
+    };
+  }
+  return {
+    fetchMode: "revalidate",
+    responseCacheControl: `public, max-age=0, s-maxage=${revalidateSeconds}, stale-while-revalidate=${Math.max(
+      revalidateSeconds * 3,
+      30,
+    )}`,
+    revalidateSeconds,
+  };
+}
+
+export const buildCityDetailProxyCachePolicy = buildForceRefreshProxyCachePolicy;
diff --git a/frontend/lib/source-freshness.ts b/frontend/lib/source-freshness.ts
new file mode 100644
index 00000000..3948c613
--- /dev/null
+++ b/frontend/lib/source-freshness.ts
@@ -0,0 +1,310 @@
+import type { CityDetail, ObservationFreshness } from "@/lib/dashboard-types";
+import { normalizeObservationSourceCode } from "@/lib/source-labels";
+
+export type MonitorFreshnessLevel = "fresh" | "aging" | "stale" | "unknown";
+export type ObservationFreshnessStatus =
+  | "fresh"
+  | "expected_wait"
+  | "delayed"
+  | "stale"
+  | "offline"
+  | "unknown";
+
+type SourceProfile = {
+  code: string;
+  label: string;
+  nativeUpdateIntervalSec: number;
+  freshWindowSec: number;
+  expectedGraceSec: number;
+  staleAfterSec: number;
+  pollIntervalSec: number;
+};
+
+const DEFAULT_SOURCE_PROFILE: SourceProfile = {
+  code: "metar",
+  label: "METAR",
+  nativeUpdateIntervalSec: 900,
+  freshWindowSec: 600,
+  expectedGraceSec: 900,
+  staleAfterSec: 3600,
+  pollIntervalSec: 300,
+};
+
+const SOURCE_PROFILES: Record<string, SourceProfile> = {
+  amos: {
+    code: "amos",
+    label: "AMOS",
+    nativeUpdateIntervalSec: 60,
+    freshWindowSec: 180,
+    expectedGraceSec: 180,
+    staleAfterSec: 900,
+    pollIntervalSec: 60,
+  },
+  jma: {
+    code: "jma",
+    label: "JMA",
+    nativeUpdateIntervalSec: 600,
+    freshWindowSec: 900,
+    expectedGraceSec: 600,
+    staleAfterSec: 2700,
+    pollIntervalSec: 300,
+  },
+  fmi: {
+    code: "fmi",
+    label: "FMI",
+    nativeUpdateIntervalSec: 600,
+    freshWindowSec: 900,
+    expectedGraceSec: 600,
+    staleAfterSec: 2700,
+    pollIntervalSec: 300,
+  },
+  knmi: {
+    code: "knmi",
+    label: "KNMI",
+    nativeUpdateIntervalSec: 600,
+    freshWindowSec: 900,
+    expectedGraceSec: 600,
+    staleAfterSec: 2700,
+    pollIntervalSec: 300,
+  },
+  hko: {
+    code: "hko",
+    label: "HKO",
+    nativeUpdateIntervalSec: 600,
+    freshWindowSec: 900,
+    expectedGraceSec: 600,
+    staleAfterSec: 2700,
+    pollIntervalSec: 300,
+  },
+  cwa: {
+    code: "cwa",
+    label: "CWA",
+    nativeUpdateIntervalSec: 600,
+    freshWindowSec: 900,
+    expectedGraceSec: 600,
+    staleAfterSec: 2700,
+    pollIntervalSec: 300,
+  },
+  mgm: {
+    code: "mgm",
+    label: "MGM",
+    nativeUpdateIntervalSec: 900,
+    freshWindowSec: 900,
+    expectedGraceSec: 900,
+    staleAfterSec: 3600,
+    pollIntervalSec: 300,
+  },
+  metar: DEFAULT_SOURCE_PROFILE,
+  noaa: DEFAULT_SOURCE_PROFILE,
+  wunderground: DEFAULT_SOURCE_PROFILE,
+  nmc: {
+    code: "nmc",
+    label: "NMC",
+    nativeUpdateIntervalSec: 3600,
+    freshWindowSec: 3600,
+    expectedGraceSec: 1800,
+    staleAfterSec: 7200,
+    pollIntervalSec: 600,
+  },
+};
+
+function canonicalSourceCode(value?: string | null) {
+  const code = normalizeObservationSourceCode(value || "metar");
+  if (!code) return "metar";
+  if (code.includes("amos")) return "amos";
+  if (code.includes("jma")) return "jma";
+  if (code.includes("fmi")) return "fmi";
+  if (code.includes("knmi")) return "knmi";
+  if (code.includes("hko")) return "hko";
+  if (code.includes("cwa")) return "cwa";
+  if (code.includes("mgm")) return "mgm";
+  if (code.includes("noaa")) return "noaa";
+  if (code.includes("nmc")) return "nmc";
+  return code;
+}
+
+export function getObservationSourceProfile(sourceCode?: string | null): SourceProfile {
+  const code = canonicalSourceCode(sourceCode);
+  return SOURCE_PROFILES[code] || { ...DEFAULT_SOURCE_PROFILE, code };
+}
+
+function parseDate(value?: string | null): Date | null {
+  const raw = String(value || "").trim();
+  if (!raw || !raw.includes("T")) return null;
+  const date = new Date(raw);
+  return Number.isFinite(date.getTime()) ? date : null;
+}
+
+function isoOrNull(date: Date | null) {
+  return date ? date.toISOString() : null;
+}
+
+export function buildObservationFreshness({
+  ageMin,
+  ingestedAt,
+  now = new Date(),
+  observedAt,
+  observedAtLocal,
+  sourceCode,
+  sourceLabel,
+}: {
+  ageMin?: number | null;
+  ingestedAt?: string | null;
+  now?: Date;
+  observedAt?: string | null;
+  observedAtLocal?: string | null;
+  sourceCode?: string | null;
+  sourceLabel?: string | null;
+}): ObservationFreshness {
+  const profile = getObservationSourceProfile(sourceCode || sourceLabel);
+  const observedDate = parseDate(observedAt || null);
+  const ageSec =
+    typeof ageMin === "number"
+      ? Math.max(0, Math.round(ageMin * 60))
+      : observedDate
+        ? Math.max(0, Math.round((now.getTime() - observedDate.getTime()) / 1000))
+        : null;
+  const expectedNext =
+    observedDate == null
+      ? null
+      : new Date(observedDate.getTime() + profile.nativeUpdateIntervalSec * 1000);
+
+  let status: ObservationFreshnessStatus = "unknown";
+  let reason = "";
+  if (ageSec == null) {
+    status = "unknown";
+    reason = "observation_time_missing";
+  } else if (ageSec <= profile.freshWindowSec) {
+    status = "fresh";
+    reason = "within_native_fresh_window";
+  } else if (ageSec <= profile.nativeUpdateIntervalSec + profile.expectedGraceSec) {
+    status = "expected_wait";
+    reason = "within_source_expected_cadence";
+  } else if (ageSec <= profile.staleAfterSec) {
+    status = "delayed";
+    reason = "past_expected_cadence";
+  } else {
+    status = "stale";
+    reason = "past_stale_threshold";
+  }
+
+  return {
+    age_sec: ageSec,
+    expected_next_update_at: isoOrNull(expectedNext),
+    freshness_reason: reason,
+    freshness_status: status,
+    ingested_at: ingestedAt || null,
+    native_update_interval_sec: profile.nativeUpdateIntervalSec,
+    observed_at: observedDate ? observedDate.toISOString() : observedAt || null,
+    observed_at_local: observedAtLocal || null,
+    source_code: profile.code,
+    source_label: sourceLabel || profile.label,
+  };
+}
+
+export function getObservationFreshness(detail?: CityDetail | null) {
+  if (!detail) return null;
+  const currentSource = canonicalSourceCode(
+    detail.current?.source_code ||
+      detail.current?.settlement_source ||
+      detail.current?.settlement_source_label ||
+      "",
+  );
+  if (
+    detail.current?.freshness &&
+    currentSource &&
+    currentSource !== "metar" &&
+    currentSource !== "wunderground"
+  ) {
+    return detail.current.freshness;
+  }
+  const embedded =
+    detail.airport_current?.freshness ||
+    detail.current?.freshness ||
+    detail.airport_primary?.freshness ||
+    null;
+  if (embedded) return embedded;
+
+  const ac = detail.airport_current;
+  const current = detail.current;
+  const sourceCode =
+    ac?.source_code ||
+    current?.settlement_source ||
+    current?.settlement_source_label ||
+    "metar";
+  const ageMin = ac?.obs_age_min ?? current?.obs_age_min ?? null;
+  return buildObservationFreshness({
+    ageMin,
+    observedAt: ac?.report_time || current?.report_time || null,
+    observedAtLocal: ac?.obs_time || current?.obs_time || null,
+    sourceCode,
+    sourceLabel: ac?.source_label || current?.settlement_source_label || undefined,
+  });
+}
+
+export function getMonitorFreshnessLevel(
+  freshness: ObservationFreshness | null | undefined,
+  fallbackAgeMin: number | null | undefined,
+): MonitorFreshnessLevel {
+  if (freshness?.freshness_status) {
+    if (freshness.freshness_status === "fresh") return "fresh";
+    if (
+      freshness.freshness_status === "expected_wait" ||
+      freshness.freshness_status === "delayed"
+    ) {
+      return "aging";
+    }
+    if (
+      freshness.freshness_status === "stale" ||
+      freshness.freshness_status === "offline"
+    ) {
+      return "stale";
+    }
+  }
+  if (fallbackAgeMin == null) return "unknown";
+  if (fallbackAgeMin < 20) return "fresh";
+  if (fallbackAgeMin < 45) return "aging";
+  return "stale";
+}
+
+function freshnessDueAt(freshness: ObservationFreshness | null | undefined) {
+  const due = parseDate(freshness?.expected_next_update_at || null);
+  return due?.getTime() ?? null;
+}
+
+export function shouldRefreshMonitorCity({
+  detail,
+  now = new Date(),
+  trigger,
+}: {
+  detail?: CityDetail | null;
+  now?: Date;
+  trigger: "initial" | "interval" | "manual";
+}) {
+  if (trigger === "initial" || trigger === "manual") return true;
+  if (!detail) return true;
+  const freshness = getObservationFreshness(detail);
+  if (
+    freshness?.freshness_status === "stale" ||
+    freshness?.freshness_status === "offline" ||
+    freshness?.freshness_status === "delayed"
+  ) {
+    return true;
+  }
+  const dueAt = freshnessDueAt(freshness);
+  if (dueAt != null) return dueAt <= now.getTime();
+
+  const ageMin = detail.airport_current?.obs_age_min ?? detail.current?.obs_age_min ?? null;
+  if (ageMin == null) return true;
+  const profile = getObservationSourceProfile(freshness?.source_code);
+  return ageMin * 60 >= profile.nativeUpdateIntervalSec;
+}
+
+export function getMonitorRefreshCadenceMs(sourceCodes: Array<string | null | undefined>) {
+  const pollSec = sourceCodes.length
+    ? Math.min(
+        ...sourceCodes.map((source) => getObservationSourceProfile(source).pollIntervalSec),
+      )
+    : 60;
+  return Math.max(60_000, pollSec * 1000);
+}
diff --git a/frontend/package.json b/frontend/package.json
index 8ab47694..8f506e3b 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -7,6 +7,7 @@
     "build": "next build && node scripts/sync-next-server-chunks.mjs",
     "start": "next start",
     "lint": "next lint",
+    "typecheck": "tsc --noEmit",
     "test:business": "node scripts/run-business-state-tests.mjs"
   },
   "dependencies": {
diff --git a/web/analysis_service.py b/web/analysis_service.py
index 4671617e..5e032c13 100644
--- a/web/analysis_service.py
+++ b/web/analysis_service.py
@@ -150,6 +150,185 @@ def _metar_is_current_local_day(
     return local_dt.strftime("%Y-%m-%d") == local_date
 
 
+_OBSERVATION_SOURCE_PROFILES: Dict[str, Dict[str, Any]] = {
+    "amos": {
+        "label": "AMOS",
+        "native_update_interval_sec": 60,
+        "fresh_window_sec": 180,
+        "expected_grace_sec": 180,
+        "stale_after_sec": 900,
+    },
+    "jma": {
+        "label": "JMA",
+        "native_update_interval_sec": 600,
+        "fresh_window_sec": 900,
+        "expected_grace_sec": 600,
+        "stale_after_sec": 2700,
+    },
+    "fmi": {
+        "label": "FMI",
+        "native_update_interval_sec": 600,
+        "fresh_window_sec": 900,
+        "expected_grace_sec": 600,
+        "stale_after_sec": 2700,
+    },
+    "knmi": {
+        "label": "KNMI",
+        "native_update_interval_sec": 600,
+        "fresh_window_sec": 900,
+        "expected_grace_sec": 600,
+        "stale_after_sec": 2700,
+    },
+    "hko": {
+        "label": "HKO",
+        "native_update_interval_sec": 600,
+        "fresh_window_sec": 900,
+        "expected_grace_sec": 600,
+        "stale_after_sec": 2700,
+    },
+    "cwa": {
+        "label": "CWA",
+        "native_update_interval_sec": 600,
+        "fresh_window_sec": 900,
+        "expected_grace_sec": 600,
+        "stale_after_sec": 2700,
+    },
+    "mgm": {
+        "label": "MGM",
+        "native_update_interval_sec": 900,
+        "fresh_window_sec": 900,
+        "expected_grace_sec": 900,
+        "stale_after_sec": 3600,
+    },
+    "metar": {
+        "label": "METAR",
+        "native_update_interval_sec": 900,
+        "fresh_window_sec": 600,
+        "expected_grace_sec": 900,
+        "stale_after_sec": 3600,
+    },
+    "noaa": {
+        "label": "NOAA",
+        "native_update_interval_sec": 900,
+        "fresh_window_sec": 600,
+        "expected_grace_sec": 900,
+        "stale_after_sec": 3600,
+    },
+    "wunderground": {
+        "label": "METAR",
+        "native_update_interval_sec": 900,
+        "fresh_window_sec": 600,
+        "expected_grace_sec": 900,
+        "stale_after_sec": 3600,
+    },
+    "nmc": {
+        "label": "NMC",
+        "native_update_interval_sec": 3600,
+        "fresh_window_sec": 3600,
+        "expected_grace_sec": 1800,
+        "stale_after_sec": 7200,
+    },
+}
+
+
+def _canonical_observation_source_code(value: Any) -> str:
+    raw = str(value or "").strip().lower()
+    if not raw:
+        return "metar"
+    if "amos" in raw:
+        return "amos"
+    if "jma" in raw:
+        return "jma"
+    if "fmi" in raw:
+        return "fmi"
+    if "knmi" in raw:
+        return "knmi"
+    if "hko" in raw:
+        return "hko"
+    if "cwa" in raw:
+        return "cwa"
+    if "mgm" in raw:
+        return "mgm"
+    if "noaa" in raw:
+        return "noaa"
+    if "nmc" in raw:
+        return "nmc"
+    if "wunderground" in raw or raw == "wu":
+        return "wunderground"
+    return raw
+
+
+def _observation_age_min(value: Any, now_utc: Optional[datetime] = None) -> Optional[int]:
+    obs_dt = _parse_utc_datetime(value)
+    if obs_dt is None:
+        return None
+    now = now_utc or datetime.now(timezone.utc)
+    return max(0, int((now - obs_dt).total_seconds() / 60))
+
+
+def _optional_str(value: Any) -> Optional[str]:
+    raw = str(value or "").strip()
+    return raw or None
+
+
+def _build_observation_freshness(
+    *,
+    source_code: Any,
+    source_label: Any = None,
+    observed_at: Any = None,
+    observed_at_local: Any = None,
+    ingested_at: Any = None,
+    age_min: Optional[int] = None,
+    now_utc: Optional[datetime] = None,
+) -> Dict[str, Any]:
+    code = _canonical_observation_source_code(source_code or source_label)
+    profile = _OBSERVATION_SOURCE_PROFILES.get(code) or _OBSERVATION_SOURCE_PROFILES["metar"]
+    now = now_utc or datetime.now(timezone.utc)
+    obs_dt = _parse_utc_datetime(observed_at)
+    age_sec = None
+    if age_min is not None:
+        try:
+            age_sec = max(0, int(age_min) * 60)
+        except Exception:
+            age_sec = None
+    if age_sec is None and obs_dt is not None:
+        age_sec = max(0, int((now - obs_dt).total_seconds()))
+
+    if age_sec is None:
+        status = "unknown"
+        reason = "observation_time_missing"
+    elif age_sec <= int(profile["fresh_window_sec"]):
+        status = "fresh"
+        reason = "within_native_fresh_window"
+    elif age_sec <= int(profile["native_update_interval_sec"]) + int(profile["expected_grace_sec"]):
+        status = "expected_wait"
+        reason = "within_source_expected_cadence"
+    elif age_sec <= int(profile["stale_after_sec"]):
+        status = "delayed"
+        reason = "past_expected_cadence"
+    else:
+        status = "stale"
+        reason = "past_stale_threshold"
+
+    expected_next = (
+        obs_dt + timedelta(seconds=int(profile["native_update_interval_sec"]))
+        if obs_dt is not None
+        else None
+    )
+    return {
+        "source_code": code,
+        "source_label": str(source_label or profile["label"]),
+        "observed_at": obs_dt.isoformat() if obs_dt is not None else _optional_str(observed_at),
+        "observed_at_local": _optional_str(observed_at_local),
+        "ingested_at": _optional_str(ingested_at),
+        "native_update_interval_sec": int(profile["native_update_interval_sec"]),
+        "expected_next_update_at": expected_next.isoformat() if expected_next is not None else None,
+        "freshness_status": status,
+        "freshness_reason": reason,
+        "age_sec": age_sec,
+    }
+
+
 def _record_analysis_cache_event(*, city: str, hit: bool, force_refresh: bool) -> None:
     now = datetime.now(timezone.utc).isoformat()
     with _ANALYSIS_CACHE_STATS_LOCK:
@@ -1842,6 +2021,48 @@ def _analyze(
             int(utc_offset or 0),
         )
 
+    current_obs_raw = obs_t
+    if current_source == "amos":
+        current_obs_raw = amos_data.get("observation_time")
+    elif current_source == "nmc":
+        current_obs_raw = (
+            nmc_fallback.get("publish_time")
+            or nmc_fallback.get("timestamp")
+            if isinstance(nmc_fallback, dict)
+            else None
+        )
+    current_age_min = metar_age_min
+    if current_obs_raw:
+        current_age_min = _observation_age_min(current_obs_raw, now_utc) or current_age_min
+    current_freshness = _build_observation_freshness(
+        source_code=current_source,
+        source_label=current_source_label,
+        observed_at=current_obs_raw,
+        observed_at_local=obs_time_str,
+        ingested_at=primary_current.get("receipt_time") or primary_current.get("report_time"),
+        age_min=current_age_min,
+        now_utc=now_utc,
+    )
+
+    airport_source_code = "amos" if current_source == "amos" else "metar"
+    airport_source_label = "AMOS" if current_source == "amos" else "METAR"
+    airport_obs_raw = amos_data.get("observation_time") if current_source == "amos" else (metar.get("observation_time") if metar else None)
+    airport_age_min = _observation_age_min(airport_obs_raw, now_utc) if airport_obs_raw else metar_age_min
+    if airport_age_min is None:
+        airport_age_min = metar_age_min
+    airport_temp = _sf(amos_data.get("temp_c")) if current_source == "amos" else _sf(live_mc.get("temp"))
+    if airport_temp is not None and not _is_plausible_city_temp(city, airport_temp, sym):
+        airport_temp = None
+    airport_freshness = _build_observation_freshness(
+        source_code=airport_source_code,
+        source_label=airport_source_label,
+        observed_at=airport_obs_raw,
+        observed_at_local=obs_time_str,
+        ingested_at=metar.get("receipt_time") if metar else None,
+        age_min=airport_age_min,
+        now_utc=now_utc,
+    )
+
     airport_primary_current = dict(network_snapshot.get("airport_primary_current") or {})
     if (
         airport_primary_current.get("source_code") == "metar"
@@ -2443,12 +2664,14 @@ def _analyze(
             "max_temp_time": max_temp_time,
             "raw_max_so_far": raw_settlement_max,
             "wu_settlement": wu_settle,
+            "source_code": current_source,
             "settlement_source": current_source,
             "settlement_source_label": current_source_label,
             "station_code": current_station_code,
             "station_name": current_station_name,
             "obs_time": obs_time_str,
             "obs_age_min": None if use_settlement_current else metar_age_min,
+            "freshness": current_freshness,
             "observation_status": "live" if cur_temp is not None else "missing",
             "report_time": primary_current.get("report_time"),
             "receipt_time": primary_current.get("receipt_time"),
@@ -2466,11 +2689,11 @@ def _analyze(
             "raw_metar": amos_data.get("raw_metar") if current_source == "amos" else primary_current.get("raw_metar"),
         },
         "airport_current": {
-            "temp": _sf(live_mc.get("temp")),
+            "temp": airport_temp,
             "obs_time": obs_time_str,
             "max_so_far": airport_max_so_far,
             "max_temp_time": airport_max_temp_time,
-            "obs_age_min": metar_age_min,
+            "obs_age_min": airport_age_min,
             "report_time": metar.get("report_time") if metar else None,
             "receipt_time": metar.get("receipt_time") if metar else None,
             "obs_time_epoch": metar.get("obs_time_epoch") if metar else None,
@@ -2481,7 +2704,9 @@ def _analyze(
             "visibility_mi": _sf(live_mc.get("visibility_mi")),
             "wx_desc": live_mc.get("wx_desc"),
             "raw_metar": amos_data.get("raw_metar") if current_source == "amos" else live_mc.get("raw_metar"),
-            "source_label": "AMOS" if current_source == "amos" else "METAR",
+            "source_code": airport_source_code,
+            "source_label": airport_source_label,
+            "freshness": airport_freshness,
             "stale_for_today": False if current_source == "amos" else (bool(metar) and not metar_current_is_today),
             "last_observation_local_date": metar.get("observation_local_date") if metar else None,
             "current_local_date": local_date_str,