Open-Meteo

Global weather forecast API for non-commercial use

Open-Meteo is a free, open-source weather API providing global forecasts, historical data, air quality, marine weather, and climate projections. It combines data from national weather services (DWD, NOAA, etc.) and delivers high-resolution forecasts without requiring an API key for non-commercial use. The API returns hourly and daily data with 50+ weather variables. For OpenClaw agents, Open-Meteo is the recommended free weather API. It needs no API key, has generous rate limits, provides comprehensive weather data (current, hourly, daily, historical), and includes air quality data. It's the default weather data source for the OpenClaw weather skill.

Tags: forecast, weather

Category: Weather

Use Cases

  • Build daily weather briefings with temperature, rain probability, and wind data
  • Check weather before recommending outdoor activities in morning briefings
  • Track historical weather patterns for travel planning or agriculture

Tips

  • Use the &current= parameter for a lightweight current conditions check
  • Combine with the free Geocoding API for city name lookups
  • The air quality endpoint is a bonus — get AQI data alongside weather in one integration

Known Issues & Gotchas

  • Requires coordinates, not city names — use geocoding first
  • Non-commercial use only on free tier — commercial needs a paid plan
  • No weather alerts/warnings endpoint — use national weather service APIs for severe weather

Frequently Asked Questions

Why choose Open-Meteo over OpenWeatherMap?

Open-Meteo is truly free with no API key needed, has higher free limits (10K/day vs 1K/day), includes air quality data, and provides more weather variables. OpenWeatherMap has a larger community and more third-party integrations.

Does it require coordinates or can I use city names?

The forecast API requires latitude/longitude. Use the Open-Meteo Geocoding API (also free) to convert city names to coordinates first, or use Nominatim.

Does it support historical weather data?

Yes. The Historical Weather API provides data going back to 1940 with hourly resolution. This is unusual for free weather APIs and useful for analysis.