🌤 Weather Trading Bot — Polymarket

Automated weather market trading bot for Polymarket. Finds mispriced temperature outcomes using Open-Meteo forecasts.

No SDK. No black box. Pure Python.

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Versions

bot_v1.py — Base Bot

The foundation. Scans 6 cities, fetches forecasts from Open-Meteo, finds matching temperature buckets on Polymarket, and enters trades when the market price is below the entry threshold.

No math, no complexity. Just the core logic — good for understanding how the system works.

bot_v2.py — Kelly + EV Edition (current)

Everything in v1, plus:

• Expected Value — skips trades where the math doesn't work
• Kelly Criterion — sizes positions based on edge strength, not a flat %
• Live monitor — updates simulation.json every 10s so the dashboard stays current
• Auto-exit — closes positions when price hits the exit threshold

~400 lines of pure Python.

bot_v3.py — Coming Soon

• Auto-cycle every hour — continuously scans and opens new positions
• Forecast monitoring every 10 minutes — closes positions if the forecast changes and EV goes negative
• Historical calibration — uses 10 years of weather data to validate probabilities

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How It Works

Polymarket runs markets like "Will the highest temperature in NYC be between 40–41°F on March 4?" These markets are often mispriced — the forecast says 78% likely, but the market is trading at 8 cents.

The bot:

1. Fetches 4-day forecasts from Open-Meteo (free, no API key)
2. Finds the matching temperature bucket on Polymarket
3. Calculates Expected Value — skips the trade if EV is negative
4. Calculates Kelly Criterion — sizes the position based on edge strength
5. Runs a full $1,000 simulation against real market prices before you risk anything

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Kelly + EV Logic

Expected Value — is this trade mathematically profitable?

EV = (our_probability × net_payout) − (1 − our_probability)

Kelly Criterion — how much of the balance to bet?

Kelly % = (p × b − q) / b

We use fractional Kelly (25%) and cap each position at 10% of balance.

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Installation

git clone https://github.com/alteregoeth-ai/weatherbot
cd weatherbot
pip install requests

Add your settings to config.json:

{
  "entry_threshold": 0.15,
  "exit_threshold": 0.45,
  "locations": "NYC,Chicago,Seattle,Atlanta,Dallas,Miami",
  "max_trades_per_run": 5,
  "min_hours_to_resolution": 2
}

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Usage

bot_v1.py

# Scan markets and show signals
python bot_v1.py

bot_v2.py

# Paper mode — shows signals + Kelly/EV analysis, no trades
python bot_v2.py

# Simulation mode — executes trades, updates virtual $1,000 balance
python bot_v2.py --live

# Live monitor — updates dashboard every 10s
python bot_v2.py --monitor

# Show open positions and PnL
python bot_v2.py --positions

# Reset simulation back to $1,000
python bot_v2.py --reset

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Dashboard

Run a local server in the bot folder:

python -m http.server 8000

Then open http://localhost:8000/sim_dashboard.html in your browser.

• Balance chart with floating +/- labels on each trade
• Open positions with Kelly %, EV, and price progress bar
• Full trade history with W/L tracking
• Refreshes every 10 seconds automatically

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Configuration

Parameter	Default	Description
entry_threshold	0.15	Buy below this price
exit_threshold	0.45	Sell above this price
locations	NYC,...	Cities to scan
max_trades_per_run	5	Max trades per run
min_hours_to_resolution	2	Skip if resolves too soon

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Live Trading

The bot runs in simulation mode by default. To execute real trades, add Polymarket CLOB integration:

pip install py-clob-client

Then replace the paper mode block in bot_v2.py with your CLOB buy function. Full guide in the article linked below.

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APIs Used

API	Auth	Purpose
Open-Meteo	None	Weather forecasts
Polymarket Gamma	None	Market data
Polymarket CLOB	Wallet key	Live trading (optional)

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Disclaimer

This is not financial advice. Prediction markets carry real risk. Run the simulation thoroughly before committing real capital.