Weather for any coordinate. Current (default): temperature (C), relative humidity (%), wind speed, weather code — real-time. Historical: add start_date & end_date (YYYY-MM-DD, up to 92 days per call, archive lags ~5 days) for hourly history — backtest weather-sensitive strategies (energy, agriculture, logistics). Inputs: lat, lon, start_date?, end_date?. Keyless (Open-Meteo).