Weather.
OpenWeatherMap API is a free Weather API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
Explore OpenWeather's vast range of weather APIs including the versatile One Call API 4.0. Ideal for both beginners and professionals, our APIs offer current weather, minute-by-minute forecasts, historical data archives, and future predictions. Access weather data starting from 01-01-1979, global w…
Details from openweathermap.org.

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Data from Personal Weather Stations called senseBoxes
Yes. The OpenWeatherMap API is listed in the Weather category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The OpenWeatherMap API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the OpenWeatherMap API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The OpenWeatherMap API is served over HTTPS, so it's safe to use in production.