Open-Meteo, the weather API that skips the sign-up form

What it covers

Open-Meteo pulls forecasts and historical records from national weather agencies including Germany's DWD, the US NOAA, and Meteo-France, then returns whichever model has the highest resolution for the coordinates you send it. Its docs list contributions from more than a dozen national services, plus dedicated feeds for marine conditions, air quality, and historical data reaching back to 1940.

Five endpoints cover most of what you'd reach for: forecast, historical archive, air quality, marine weather, and location search. We called all five this week with a browser-style Origin header, and each returned live data with an access-control-allow-origin: * header, matching the CORS support already recorded on GreatAPIs.

No key, no signup

Every one of those calls worked without an API key. The non-commercial tier allows a generous number of daily, hourly, and per-minute requests with no registration step at all (see the facts panel below for the exact figures); a paid tier exists for commercial use, detailed on the pricing page. That's an unusual combination for a data source this broad: most weather providers ask for a key before you see a single response.

Reading the response

Responses come back as JSON by default, with CSV, XLSX, and FlatBuffers available if you want a lighter or more structured payload. Official clients exist for Python and TypeScript if you'd rather not hand-write query strings, and the status page tracks uptime separately from the docs site.

Why it's worth a look

For a quick prototype, or a hobby project you don't want gated behind a signup, Open-Meteo removes the usual friction: no key, a request that already works from browser JavaScript, and a free tier wide enough for most personal projects. It won't replace a paid, SLA-backed provider for a production weather feature, but it's a solid default when the question is just "will it rain" or when your project shouldn't need an account at all.