Portuguese weather and climate data.
IPMA API is a free Weather API that requires no API key, is served over HTTPS and has unconfirmed CORS support.
IPMA, api, oceano, previsão, tempo, mar, meteorológica
Details from api.ipma.pt.

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Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Multi-model weather: GFS, ECMWF AIFS/IFS and a 31-member GEFS ensemble, keyless point forecasts
Radar-detected hail history for any US address from NOAA NEXRAD Level-III hail detections, by year
The IPMA API is provided by IPMA (api.ipma.pt). IPMA, api, oceano, previsão, tempo, mar, meteorológica
Yes. The IPMA 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.
No. The IPMA API requires no authentication, so you can start making requests without signing up.
CORS support for the IPMA API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The IPMA API is served over HTTPS, so it's safe to use in production.