Weather.
Weatherbit API is a free Weather API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
Weather API documentation for current weather, forecasts, historical weather data, air quality, maps, lightning, agriculture, and energy APIs.
Details from weatherbit.io.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Current weather, local time, UTC offset and DST rules for 400 cities as static JSON
The Weatherbit API is provided by Weatherbit (weatherbit.io). Weather API documentation for current weather, forecasts, historical weather data, air quality, maps, lightning, agriculture, and energy APIs.
Yes. The Weatherbit 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 Weatherbit API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the Weatherbit API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Weatherbit API is served over HTTPS, so it's safe to use in production.