# Meteomatics Weather API vs OpenWeather One Call API

> OpenWeather One Call API scores 57.4 (C) on agent readiness against Meteomatics Weather API's 49.6 (D), and leads in 4 of 7 scored categories. Meteomatics Weather API leads on agent ergonomics and security & auth. Both do weather current. Category scores, facts, verdicts and…

- Canonical: https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call
- Markdown: https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call.md (~2,800 tokens)
- Slim: https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-08

OpenWeather One Call API scores 57.4 (C) on agent readiness against Meteomatics Weather API's 49.6 (D), and leads in 4 of 7 scored categories. Meteomatics Weather API leads on agent ergonomics and security & auth. Both do weather current.

- Meteomatics Weather API: grade D, 49.6/100, rank #606 of 722. Markdown https://www.anchorterminal.com/tools/meteomatics.md · JSON https://www.anchorterminal.com/api/v1/tools/meteomatics.json
- OpenWeather One Call API: grade C, 57.4/100, rank #474 of 722. Markdown https://www.anchorterminal.com/tools/openweather-one-call.md · JSON https://www.anchorterminal.com/api/v1/tools/openweather-one-call.json

## Which one, for what

### Meteomatics Weather API (D)

Good for: Companies in energy, aviation, insurance and logistics that need many models, long history, polygon and route queries and an SLA, and will buy by contract.

Ahead on:
- Agent ergonomics, 80 against 73
- Security & auth, 54 against 42

Watch for: No public price, free tier or self-serve signup found. Credentials arrive by email after a sales conversation

### OpenWeather One Call API (C)

Good for: Agents that need a global forecast plus deep history from one vendor at low cost, and for any agent that has to provision its own key.

Ahead on:
- Reliability, 45 against 34
- Payments & pricing, 60 against 0
- Maintenance & community, 60 against 42

Also in its favour:
- Free to start without a card

Watch for: The main API takes the key only as the appid query parameter


## Score by category

| Category | Weight | Meteomatics Weather API | OpenWeather One Call API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 34 | 45 | OpenWeather One Call API +11 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 71 | 68 | Meteomatics Weather API +3 |
| Agent ergonomics | 13% (16.2 this run) | 80 | 73 | Meteomatics Weather API +7 |
| Security & auth | 14% (17.5 this run) | 54 | 42 | Meteomatics Weather API +12 |
| Payments & pricing | 10% (12.5 this run) | 0 | 60 | OpenWeather One Call API +60 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 42 | 60 | OpenWeather One Call API +18 |
| Transparency & trust | 7% (8.8 this run) | 59 | 61 | OpenWeather One Call API +2 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **49.6 · D** | **57.4 · C** | |

## Facts side by side

| Fact | Meteomatics Weather API | OpenWeather One Call API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Meteomatics AG | OpenWeather |
| Hosted endpoint | `https://api.meteomatics.com` | `https://api.openweathermap.org/data/3.0/onecall` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Meteomatics' general terms and conditions. The Python connector on GitHub is MIT | none |
| Tools exposed | 9 | 6 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | `org.openweathermap/agents` |
| Last release | 2026-08-24 | none |
| Terms last updated | no date given |  |
| Privacy policy last updated | no date given | 2022-07-18 |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | 56 stars, 16k PyPI/wk | none |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**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.

**OpenWeather One Call API.** 1,000 free calls a day, then $0.0015 a call, or $0.001 on the agent lane. The main API takes the key only as the appid query parameter.

## Before you call either

### 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

### OpenWeather One Call API

1. Sign up on the agent lane with POST https://agents.openweathermap.org/v1/accounts and keep the data key. It's shown once
2. Check GET https://data.openweathermap.org/account/balance for credit. No data response carries a cost or balance
3. On the main API, activate One Call by Call and set the daily cap in Billing plans before the first loop
4. Pass units=metric. The default is Kelvin
5. Use exclude=minutely,alerts on 3.0, or the 4.0 timeline step you need, to shrink responses

## Questions

### Which is better for AI agents, Meteomatics Weather API or OpenWeather One Call API?

OpenWeather One Call API scores 57.4 (C) on agent readiness against Meteomatics Weather API's 49.6 (D), and leads in 4 of 7 scored categories. Meteomatics Weather API leads on agent ergonomics and security & auth.

### Do Meteomatics Weather API and OpenWeather One Call API need an API key?

Meteomatics Weather API takes an API key or an OAuth sign-in. OpenWeather One Call API needs an API key.

### Can an agent call Meteomatics Weather API and OpenWeather One Call API without installing anything?

Yes. Meteomatics Weather API has a hosted endpoint at https://api.meteomatics.com and OpenWeather One Call API at https://api.openweathermap.org/data/3.0/onecall.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call.json, and with the fewest tokens: https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "meteomatics", "b": "openweather-one-call"}`. From a terminal: `anchor compare meteomatics openweather-one-call`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/meteomatics.json and https://www.anchorterminal.com/api/v1/tools/openweather-one-call.json

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