What is polymarket-weather-trading-engine?

WeatherBet is an automated trading bot written in TypeScript that bets on Polymarket weather prediction markets, markets where people place wagers on whether a city's temperature will land in a specific range on a given day. The bot's strategy is to find markets where the crowd's implied probability differs meaningfully from what weather forecast models predict, then place bets on the more accurate estimate. To do this, it pulls data from three weather forecast sources covering 20 cities and cross-references those forecasts with real airport weather station readings (using official aviation weather stations, since Polymarket resolves its temperature markets based on airport readings rather than generic city-center coordinates). It then calculates the expected value of each potential trade, sizes positions using Kelly criterion (a mathematical formula that scales bet size based on how large your edge is), and applies stop-loss rules to limit downside. By default the bot runs in paper-trading mode (simulated, no real money), which lets you test the strategy. Setting a live-trading environment variable and providing a Polymarket wallet key enables real trades through Polymarket's order book. Every forecast, trade, and outcome is saved to local JSON files, and the bot uses that history to recalibrate its models over time. It runs on Node.js 20.10 or newer. The README notes this is not financial advice and recommends paper trading until you understand the risk.