Met Office Weather DataHub (Site Specific) vs Xweather Weather API

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.

Xweather Weather API

A public OpenAPI file with 236 operations, a hosted MCP server in the official registry and a free tier of 15,000 accesses a month suit agents. REST credentials travel only in the query string, per-minute limits are unpublished, and the group terms bar commercial use of free plans and passing data to third parties unless a service description allows it.

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

Xweather Weather API

1. Check success and error.code on every response. Application errors such as invalid_location return HTTP 200 with success false
2. Send fields, limit and plimit. The docs put a 15-day hourly forecast at about 600 KB, and about 25 KB with three fields
3. Read X-Cost-Tokens after each call. Cost is the endpoint multiplier times the intervals requested, so narrow from and to
4. For MCP, send Authorization: Bearer <client_id>_<client_secret> and avoid the api_key query parameter, which puts the secret in the URL
5. Add include_tags or include_tools to the MCP URL to load only the tool groups the task needs
6. On 429 read Retry-After and the X-RateLimit-Reset-* headers. maxhits_min clears at the next minute, maxhits at the period reset