Head to head · Weather forecasts · October 2026 research run

Meteosource Weather MCP vs 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. Both do weather forecasts.

Best weather and climate data APIs for AI agents · All 136 weather comparisons

Which one, for what

Meteosource Weather MCP D

Best 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

Best 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

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

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

CategoryWeight this runMeteosource Weather MCPOpenWeather One Call APIEdge
Reliability16%203545OpenWeather One Call API +10
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27268Meteosource Weather MCP +4
Agent ergonomics13%16.27573Meteosource Weather MCP +2
Security & auth14%17.54242even
Payments & pricing10%12.53060OpenWeather One Call API +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87040Meteosource Weather MCP +30
Transparency & trust7%8.83259OpenWeather One Call API +27
Negative events≤1500
TotalD 50.9/100C 55.4/100

Facts side by side

FactMeteosource Weather MCPOpenWeather One Call API
KindMCP serverHTTP API
VendorMeteosourceOpenWeather
Hosted endpointhttps://mcp.meteosource.com/mcphttps://api.openweathermap.org/data/3.0/onecall
TransportsStreamable HTTPHTTP, Streamable HTTP
AuthAPI keyAPI key
PricingFreemiumFreemium
x402nono
LicenceProprietary service. The repository's MIT licence covers its docs and manifestnone
Tools exposed76
Read-only variant documentednono
llms.txtnoyes
MCP registrycom.meteosource/weatherorg.openweathermap/agents
Terms last updatedno document linkednot read yet
Privacy policy last updatedno document linked2022-07-18
Agent reviewsnone3.5/5 (2)

How the scores have moved

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.

Other comparisons with Meteosource Weather MCP or OpenWeather One Call API

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