OpenWeatherMap

Weather

OpenWeatherMap is one of the most popular weather APIs, providing current weather, forecasts (hourly, daily, 16-day), historical data, air pollution, weather maps, and severe weather alerts. It covers any location worldwide using city names, coordinates, or ZIP codes. Authentication uses a simple API key. For OpenClaw agents, OpenWeatherMap is a well-established weather integration with extensive documentation and community support. The free tier covers basic current weather and 5-day forecasts — sufficient for daily briefings and weather-aware scheduling. Its main advantage over Open-Meteo is accepting city names directly without geocoding.

Tags: forecast, weather

Category: Weather

Use Cases

  • Check current weather conditions by city name for daily briefings
  • Get 5-day forecasts for travel planning and scheduling
  • Monitor air pollution levels alongside weather data

Tips

  • Use &units=metric for Celsius or &units=imperial for Fahrenheit
  • The free 5-day/3-hour forecast endpoint is sufficient for most agent weather skills
  • Cache weather data for at least 10-30 minutes — conditions don't change faster than that

Known Issues & Gotchas

  • API key takes up to 2 hours to activate after registration
  • One Call API 3.0 (hourly forecasts, alerts) is billed separately per call
  • Free tier doesn't include hourly forecasts — only 3-hour intervals in the 5-day forecast

Frequently Asked Questions

How does OpenWeatherMap compare to Open-Meteo?

OpenWeatherMap accepts city names directly (easier), has weather alerts, and more third-party integrations. Open-Meteo is free without a key, has higher free limits, and includes more weather variables. For OpenClaw, Open-Meteo is often the better free choice.

Is 1,000 calls/day enough?

Yes, for personal agent use. A few weather checks per day plus hourly forecasts would use maybe 20-30 calls. You'd only hit the limit with very frequent automated polling.

Does it support weather alerts?

Yes. The One Call API 3.0 includes government-issued weather alerts for severe conditions. This requires a paid subscription (One Call by Call billing).