Met Office Weather DataHub (Site Specific) vs NOAA National Weather Service API (api.weather.gov)

Met Office Weather DataHub (Site Specific)

Statutory UK weather service, with a FAQ licence to copy, publish and adapt the data. No OpenAPI, llms.txt, SDK or MCP server.

NOAA National Weather Service API (api.weather.gov)

Free, no key and no account, with public domain data. US and territories only.

Met Office Weather DataHub (Site Specific)

1. Register an application and subscribe it to the Global Spot plan first. The key is tied to that order and shown once
2. Send the key in the apikey header with Accept: application/json, and latitude and longitude as query parameters
3. Add excludeParameterMetadata=true to drop the parameter descriptions from every response
4. Pick the timestep by need. hourly covers 48 hours, three-hourly 168, daily 7 days, and each call counts against the daily limit
5. Stop on a 429. The limit is daily and resets at 00:00 UTC

NOAA National Weather Service API (api.weather.gov)

1. Set User-Agent to your app name and a contact email or the request is refused with 403
2. Cache the /points response per coordinate. The office and grid rarely change
3. Round coordinates to four decimal places. More precision returns an error
4. Don't add cache-busting query parameters. Unknown parameters return 400
5. Back off about five seconds after a throttled request and reuse the last good response