diff --git a/src/data_collection/amos_station_sources.py b/src/data_collection/amos_station_sources.py
index 9d63bf1d..a28fabf6 100644
--- a/src/data_collection/amos_station_sources.py
+++ b/src/data_collection/amos_station_sources.py
@@ -333,8 +333,6 @@ def _amos_parse_runway_table(text: str) -> dict[str, Any]:
 class AmosStationSourceMixin:
     """Mixin that adds AMOS runway-level data fetching to WeatherDataCollector."""
 
-    amos_cache_ttl_sec: int = 300  # 5 minutes
-
     def _amos_get_page(self, icao: str) -> Optional[str]:
         """Fetch the AMOS page.
 
diff --git a/web/analysis_service.py b/web/analysis_service.py
index 3a71cef8..4671617e 100644
--- a/web/analysis_service.py
+++ b/web/analysis_service.py
@@ -18,6 +18,7 @@ from web.core import (
     _cache,
     CACHE_TTL,
     CACHE_TTL_ANKARA,
+    CACHE_TTL_KOREAN_AMOS,
     CITIES,
     CITY_RISK_PROFILES,
     SETTLEMENT_SOURCE_LABELS,
@@ -177,8 +178,16 @@ def get_analysis_cache_stats() -> Dict[str, Any]:
     return stats
 
 
+KOREAN_AMOS_CITIES = {"seoul", "busan"}
+
+
 def _analysis_ttl_for_city(city: str) -> int:
-    return CACHE_TTL_ANKARA if city.lower() in TURKISH_MGM_CITIES else CACHE_TTL
+    city_lower = city.lower()
+    if city_lower in TURKISH_MGM_CITIES:
+        return CACHE_TTL_ANKARA
+    if city_lower in KOREAN_AMOS_CITIES:
+        return CACHE_TTL_KOREAN_AMOS
+    return CACHE_TTL
 
 
 def _analysis_cache_key(city: str, detail_mode: str = "full") -> str:
@@ -1617,7 +1626,7 @@ def _analyze(
 ) -> Dict[str, Any]:
     """Fetch, analyse, and return structured weather data for one city."""
     # Check cache
-    ttl = CACHE_TTL_ANKARA if city.lower() in TURKISH_MGM_CITIES else CACHE_TTL
+    ttl = _analysis_ttl_for_city(city)
     normalized_detail_mode_raw = str(detail_mode or "full").strip().lower()
     if normalized_detail_mode_raw == "panel":
         normalized_detail_mode = "panel"
diff --git a/web/core.py b/web/core.py
index 2de58e53..742008af 100644
--- a/web/core.py
+++ b/web/core.py
@@ -86,6 +86,7 @@ SETTLEMENT_SOURCE_LABELS: Dict[str, str] = {
 _cache: Dict[str, Dict] = {}
 CACHE_TTL = 300
 CACHE_TTL_ANKARA = 60
+CACHE_TTL_KOREAN_AMOS = 60
 _PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 _PROBABILITY_EVALUATION_REPORT = os.path.join(
     _PROJECT_ROOT,