Meteomatics Weather API vs Open-Meteo

Meteomatics Weather API

A public OpenAPI file, a hosted MCP server whose nine tools are all marked read-only, a published SLA with compensation and ISO 27001 certification suit company use. Access needs a sales contract, with no public price, free tier or self-serve signup found, no status page, and REST calls that authenticate with a username and password.

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.

Meteomatics Weather API

1. Ask the account owner for credentials first. There is no signup, and both the REST API and the MCP server need a Meteomatics account with API access
2. Build REST URLs as validdatetime/parameters/location/format, for example 2026-10-08T00:00:00Z/t_2m:C/52.52,13.40/json. Parameter names carry their unit after a colon
3. Keep each query to 10 locations and 10 parameters unless the contract says otherwise, and use POST when a GET URL passes 2,000 characters
4. Send credentials or the token in the Authorization header. Avoid the documented access_token query parameter, which puts the token in URLs and logs
5. Read /user_stats_json before a large job. It reports queries sent and the contract's limits, and 429 means a limit is spent
6. Treat reserved values such as -888 and -999 as invalid or missing data, and shrink the request when a 408 arrives after the 300-second timeout

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