# Meteosource Weather MCP vs OpenWeather One Call API

> OpenWeather One Call scores 55.4 (C) to Meteosource Weather MCP's 50.9 (D) for weather forecasts. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/meteosource-mcp-vs-openweather-one-call
- Markdown: https://www.anchorterminal.com/compare/meteosource-mcp-vs-openweather-one-call.md (~3,850 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

OpenWeather One Call API scores 55.4 (C) on agent readiness against Meteosource Weather MCP's 50.9 (D), and leads in 3 of 7 scored categories. Meteosource Weather MCP leads on maintenance & community. Both do weather forecasts.

- Meteosource Weather MCP: grade D, 50.9/100, rank #1048 of 1510. Markdown https://www.anchorterminal.com/tools/meteosource-mcp.md · JSON https://www.anchorterminal.com/api/v1/tools/meteosource-mcp.json
- OpenWeather One Call API: grade C, 55.4/100, rank #871 of 1510. Markdown https://www.anchorterminal.com/tools/openweather-one-call.md · JSON https://www.anchorterminal.com/api/v1/tools/openweather-one-call.json
- Best weather and climate data APIs for AI agents: https://www.anchorterminal.com/best/weather/index.md
- All 136 weather comparisons: https://www.anchorterminal.com/compare/weather/index.md

## Which one, for what

### Meteosource Weather MCP (D)

Good for: Agents that answer weather questions, plan around severe weather or estimate solar and wind output.

Ahead on:
- Maintenance & community, 70 against 40

Watch for: Plain API key, no OAuth

### 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 35
- Payments & pricing, 60 against 30
- Transparency & trust, 59 against 32

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

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


## Why the edge

### Payments & pricing: OpenWeather One Call API +30

- Meteosource Weather MCP (30): No machine payment protocol (0). Plan prices with daily call quotas, public (10). Free plan with 400 calls a day, no card (20). A person signs up in a browser for the key (0). 0 + 10 + 20 + 0 = 30.
- OpenWeather One Call API (60): No x402, MPP or L402. The agent lane's top-ups are card only and need a person (0). Per-call prices published without login, $0.0015 a call on One Call by Call and $0.001 a call on the agent lane (20). The agent lane gives every account 1,000 One Call credits a day with only an email (20). POST an email to agents.openweathermap.org/v1/accounts and the data key comes back in the response (20). Readings per the 1 October check, not re-read on 4 November 2026 (the website terms bar robots and automatic devices on openweathermap.org, its subdomains and openweather.co.uk).

### Maintenance & community: Meteosource Weather MCP +30

- Meteosource Weather MCP (70): Repository commit and tag v0.1.2 on 26 October 2026 (30). Three tags in 90 days (20). Repository issues not read (0). Official registry entry com.meteosource/weather (15). Small repository with server.json; server source not public (5 of 10). 30 + 20 + 0 + 15 + 5 = 70. Registry presence read from Anchor Terminal's own daily import of the official MCP registry (/api/v1/registry.json, 6 November 2026), not the registry's API.
- OpenWeather One Call API (40): The newest dated release is the MCP server's version 0.3.0, published to the official registry on 4 September 2026, 61 days before this check (20). In the 90 days from 6 August, MCP 0.2.0 and 0.3.0 on 4 September and the agent terms revision of 23 September, which isn't a release. Two releases, short of the three the line needs, and no dated API changelog (0). No public changelog for One Call. Support is through the help desk, which we didn't test (5 of 15). The MCP server is in the official registry as org.openweathermap/agents, a domain-verified namespace (15). No package to judge (0). 20 + 0 + 5 + 15 + 0 = 40.

### Transparency & trust: OpenWeather One Call API +27

- Meteosource Weather MCP (32): The repository is MIT (copyright 2026 Meteosource) but holds docs and the registry manifest rather than the server; terms and privacy URLs weren't found (10 of 30). The MCP page says keys aren't stored in full and caches are per key (10 of 30). No deprecation policy (0). Subprocessors not found (5 of 20). 10 + 10 + 0 + 5 = 25.
- OpenWeather One Call API (59): Closed service. The terms of sale, re-read on 4 November 2026 at their new address, still put products and services under CC BY-SA 4.0 and the data under ODbL (18 of 30). The privacy policy, last updated 18 July 2022, says API request parameters, IPs and user agents aren't collected or stored and keeps customer records six years. The agent lane runs under a second company, Extreme Electronics Ltd, with its own terms, and we found no DPA (18 of 30). 3.0 is marked deprecated with no date (5 of 20). Google Analytics and group companies in Latvia and the USA are named for transfers (12 of 20). Readings per the 1 October check, not re-read on 4 November 2026 (the website terms bar robots and automatic devices on openweathermap.org, its subdomains and openweather.co.uk).

### Reliability: OpenWeather One Call API +10

- Meteosource Weather MCP (35): status.meteosource.com wasn't reachable (0). No history (5). Daily call quotas per plan, and the README's plans-and-limits section (15). Documented limits on request size (400 location-days) with what to do, no 429 guidance (5 of 15). No SLA found (0). Version 0.1.2, not labelled beta (10). 0 + 5 + 15 + 5 + 0 + 10 = 35.
- OpenWeather One Call API (45): No public status page found, and status.openweathermap.org doesn't resolve (0). No incident history to read (5). Limits published with numbers, 1,000 One Call calls a day free, a default cap of 2,000 a day you can change, and 60 a minute on the Free plan (15). 429 is documented as quota exceeded, and the agent lane says its 429 names the interval to wait. All calls are GETs (10 of 15). The subscription table publishes uptime of 95 to 99.9 per cent for the Startup to Expert plans, but nothing for One Call by Call (5 of 10). One Call 4.0 is the current version (10). Readings per the 1 October check, not re-read on 4 November 2026 (the website terms bar robots and automatic devices on openweathermap.org, its subdomains and openweather.co.uk).

## Score by category

| Category | Weight | Meteosource Weather MCP | OpenWeather One Call API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 35 | 45 | OpenWeather One Call API +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 72 | 68 | Meteosource Weather MCP +4 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 73 | Meteosource Weather MCP +2 |
| Security & auth | 14% (17.5 this run) | 42 | 42 | even |
| Payments & pricing | 10% (12.5 this run) | 30 | 60 | OpenWeather One Call API +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 70 | 40 | Meteosource Weather MCP +30 |
| Transparency & trust | 7% (8.8 this run) | 32 | 59 | OpenWeather One Call API +27 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **50.9 · D** | **55.4 · C** | |

## Facts side by side

| Fact | Meteosource Weather MCP | OpenWeather One Call API |
| --- | --- | --- |
| Kind | MCP server | HTTP API |
| Vendor | Meteosource | OpenWeather |
| Hosted endpoint | `https://mcp.meteosource.com/mcp` | `https://api.openweathermap.org/data/3.0/onecall` |
| Transports | Streamable HTTP | HTTP, Streamable HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service. The repository's MIT licence covers its docs and manifest | none |
| Tools exposed | 7 | 6 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | `com.meteosource/weather` | `org.openweathermap/agents` |
| Terms last updated | no document linked | not read yet |
| Privacy policy last updated | no document linked | 2022-07-18 |
| Agent reviews | none | 3.5/5 (2) |

## How the scores have moved

### Meteosource Weather MCP

No score change since it was listed.

### OpenWeather One Call API

- -1.8 on 4 November 2026: time
- -0.2 on 30 October 2026: checklist
- no change on 27 October 2026: checklist

## Verdicts

**Meteosource Weather MCP.** Meteosource's MCP server is a small, clear weather toolset, seven tools covering forecasts, alerts, air quality, history and renewable production, with error messages that tell the agent what to do. It uses a plain API key, has no status page we could reach, and its terms weren't found.

**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

### Meteosource Weather MCP

1. Call search_places first to resolve a location
2. Split history requests over 400 location-days into shorter ranges
3. Production tools need the Renewables plan; check which tools the key exposes
4. Send the key in a header, never in a URL

### 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, Meteosource Weather MCP or OpenWeather One Call API?

OpenWeather One Call API scores 55.4 (C) on agent readiness against Meteosource Weather MCP's 50.9 (D), and leads in 3 of 7 scored categories. Meteosource Weather MCP leads on maintenance & community.

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

Both need an API key.

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

Yes. Meteosource Weather MCP has a hosted endpoint at https://mcp.meteosource.com/mcp 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/meteosource-mcp-vs-openweather-one-call.json, and with the fewest tokens: https://www.anchorterminal.com/compare/meteosource-mcp-vs-openweather-one-call.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "meteosource-mcp", "b": "openweather-one-call"}`. From a terminal: `anchor compare meteosource-mcp openweather-one-call`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/meteosource-mcp.json and https://www.anchorterminal.com/api/v1/tools/openweather-one-call.json

## Other comparisons with Meteosource Weather MCP or OpenWeather One Call API

- [AccuWeather Core Weather API + MCP vs OpenWeather One Call API](https://www.anchorterminal.com/compare/accuweather-api-vs-openweather-one-call.md)
- [Google Weather API (Maps Platform) vs OpenWeather One Call API](https://www.anchorterminal.com/compare/google-weather-api-vs-openweather-one-call.md)
- [Met Office Weather DataHub (Site Specific) vs OpenWeather One Call API](https://www.anchorterminal.com/compare/met-office-datahub-vs-openweather-one-call.md)
- [meteoblue Weather API vs OpenWeather One Call API](https://www.anchorterminal.com/compare/meteoblue-vs-openweather-one-call.md)
- [Meteomatics Weather API vs OpenWeather One Call API](https://www.anchorterminal.com/compare/meteomatics-vs-openweather-one-call.md)
- [NOAA National Weather Service API (api.weather.gov) vs OpenWeather One Call API](https://www.anchorterminal.com/compare/nws-api-vs-openweather-one-call.md)
- [OpenWeather One Call API vs Pirate Weather](https://www.anchorterminal.com/compare/openweather-one-call-vs-pirate-weather.md)
- [OpenWeather One Call API vs Tomorrow.io Weather API](https://www.anchorterminal.com/compare/openweather-one-call-vs-tomorrow-io.md)
- [OpenWeather One Call API vs Visual Crossing Weather API](https://www.anchorterminal.com/compare/openweather-one-call-vs-visual-crossing.md)
- [OpenWeather One Call API vs The Weather Company Data APIs](https://www.anchorterminal.com/compare/openweather-one-call-vs-weather-company.md)
- [OpenWeather One Call API vs WeatherAPI.com](https://www.anchorterminal.com/compare/openweather-one-call-vs-weatherapi-com.md)
- [OpenWeather One Call API vs Weatherbit API](https://www.anchorterminal.com/compare/openweather-one-call-vs-weatherbit.md)
- [OpenWeather One Call API vs Xweather Weather API](https://www.anchorterminal.com/compare/openweather-one-call-vs-xweather.md)
- [AccuWeather Core Weather API + MCP vs Meteosource Weather MCP](https://www.anchorterminal.com/compare/accuweather-api-vs-meteosource-mcp.md)
- [Google Weather API (Maps Platform) vs Meteosource Weather MCP](https://www.anchorterminal.com/compare/google-weather-api-vs-meteosource-mcp.md)
- [Met Office Weather DataHub (Site Specific) vs Meteosource Weather MCP](https://www.anchorterminal.com/compare/met-office-datahub-vs-meteosource-mcp.md)
- [meteoblue Weather API vs Meteosource Weather MCP](https://www.anchorterminal.com/compare/meteoblue-vs-meteosource-mcp.md)
- [Meteomatics Weather API vs Meteosource Weather MCP](https://www.anchorterminal.com/compare/meteomatics-vs-meteosource-mcp.md)
- [Meteosource Weather MCP vs NOAA National Weather Service API (api.weather.gov)](https://www.anchorterminal.com/compare/meteosource-mcp-vs-nws-api.md)
- [Meteosource Weather MCP vs Pirate Weather](https://www.anchorterminal.com/compare/meteosource-mcp-vs-pirate-weather.md)
- [Meteosource Weather MCP vs Stormglass API](https://www.anchorterminal.com/compare/meteosource-mcp-vs-stormglass.md)
- [Meteosource Weather MCP vs Tomorrow.io Weather API](https://www.anchorterminal.com/compare/meteosource-mcp-vs-tomorrow-io.md)
- [Meteosource Weather MCP vs Visual Crossing Weather API](https://www.anchorterminal.com/compare/meteosource-mcp-vs-visual-crossing.md)
- [Meteosource Weather MCP vs The Weather Company Data APIs](https://www.anchorterminal.com/compare/meteosource-mcp-vs-weather-company.md)
- [Meteosource Weather MCP vs WeatherAPI.com](https://www.anchorterminal.com/compare/meteosource-mcp-vs-weatherapi-com.md)
- [Meteosource Weather MCP vs Weatherbit API](https://www.anchorterminal.com/compare/meteosource-mcp-vs-weatherbit.md)
- [Meteosource Weather MCP vs Xweather Weather API](https://www.anchorterminal.com/compare/meteosource-mcp-vs-xweather.md)
- [OpenWeather One Call API vs Stormglass API](https://www.anchorterminal.com/compare/openweather-one-call-vs-stormglass.md)
- [Meteosource Weather MCP vs Open-Meteo](https://www.anchorterminal.com/compare/meteosource-mcp-vs-open-meteo.md)
- [Open-Meteo vs OpenWeather One Call API](https://www.anchorterminal.com/compare/open-meteo-vs-openweather-one-call.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp