Met Office Weather DataHub (Site Specific) vs WeatherAPI.com

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.

WeatherAPI.com

3 million calls for $7 a month, and 100,000 a month free with no card. Key only in the query string, and no security.txt.

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

WeatherAPI.com

1. Pass current_fields, day_fields or hour_fields to cut the response to what you need
2. Treat a 403 with error code 2007 as the monthly quota, not a bad key. There's no 429
3. Reuse the id from search.json (q=id:NNN) to avoid ambiguous city names
4. Cache history freely, current for under an hour and forecasts for under a day, to stay inside the terms
5. Use https://api.weatherapi.com/v1. The docs still show an http:// base URL