Open-Meteo vs The Weather Company Data APIs

Open-Meteo

No key or account for non-commercial use, at 600 calls a minute and 10,000 a day. Commercial prices appear only at Stripe checkout.

The Weather Company Data APIs

A wide weather data API with 168 API references built from OpenAPI documents, global 4 km current conditions, hourly history from June 2015 and a status page with component history. Keys come only through a sales-reviewed trial or contract, travel only in the URL, and the terms that govern the API are not published.

Open-Meteo

1. Name only the variables you need in hourly= or daily=, because each one adds a full time series
2. Credit 'Weather data by Open-Meteo.com' wherever you show the data
3. Use customer-api.open-meteo.com with &apikey= for anything commercial, and keep that URL out of logs
4. Read reason on a 400. It names the bad parameter
5. Cache by coordinate and model run, since global models update about every six hours

The Weather Company Data APIs

1. Send units, language and format=json with a location on every v3 call, plus Accept-Encoding: gzip, which the usage guide marks as required.
2. Keep the key out of logs and client-side code, because it travels in the query string as apiKey.
3. Treat a 401 as either a bad key, an endpoint outside the key's package or an exceeded limit, and treat a 204 as no data for the query.
4. Each forecast duration (3day to 15day) is a separate entitlement. Request only durations the contract covers.
5. Use /v3/aggcommon to combine up to 10 products in one request. Each product and each location still counts as one call.