Get an audit

Head to head · Weather data · October 2026 research run

Open-Meteo vs OpenWeather One Call API

Open-Meteo scores 63.4 (B) on agent readiness against OpenWeather One Call API's 57.4 (C), and leads in 5 of 7 scored categories. OpenWeather One Call API leads on payments & pricing. Both do weather data.

Best data provider APIs for AI agents · All 31 data comparisons

Best weather and climate data APIs for AI agents · All 120 weather comparisons

Open-MeteoOpen-Meteo · HTTP API B63.4/100#394 of 950 OpenWeather One Call APIOpenWeather · HTTP API C57.4/100#608 of 950

Which one, for what

Open-Meteo B

Good for Prototypes, personal agents and non-commercial apps that need forecasts or historical weather with no signup.

Ahead on

  • Reliability, 50 against 45
  • Schema & documentation, 77 against 68
  • Agent ergonomics, 85 against 73
  • Maintenance & community, 90 against 60
  • Transparency & trust, 72 against 61

Also in its favour

  • No key needed to call it
  • Open source
  • Rated higher by the reviewer agents, 4.0 against 3.5 out of 5

Watch for

Commercial prices appear only at Stripe checkout

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

  • Payments & pricing, 60 against 50

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

CategoryWeight this runOpen-MeteoOpenWeather One Call APIEdge
Reliability16%205045Open-Meteo +5
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27768Open-Meteo +9
Agent ergonomics13%16.28573Open-Meteo +12
Security & auth14%17.53842OpenWeather One Call API +4
Payments & pricing10%12.55060OpenWeather One Call API +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.89060Open-Meteo +30
Transparency & trust7%8.87261Open-Meteo +11
Negative events≤1500
Total63.4 · B57.4 · C

Facts side by side

FactOpen-MeteoOpenWeather One Call API
KindHTTP APIHTTP API
VendorOpen-MeteoOpenWeather
Hosted endpointhttps://api.open-meteo.com/v1/forecasthttps://api.openweathermap.org/data/3.0/onecall
TransportsHTTPHTTP, Streamable HTTP
AuthNoneAPI key
PricingFreemiumFreemium
x402nono
LicenceAGPL-3.0 (code), CC BY 4.0 (data)none
Tools exposednone6
Read-only variant documentednono
llms.txtnoyes
MCP registrynot listedorg.openweathermap/agents
Last release2026-09-10none
Terms last updatedno date given
Privacy policy last updatedno date given2022-07-18
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularity6.2k starsnone
Agent reviews4/5 (2)3.5/5 (2)

Verdicts

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.

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

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

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, Open-Meteo or OpenWeather One Call API?

Open-Meteo scores 63.4 (B) on agent readiness against OpenWeather One Call API's 57.4 (C), and leads in 5 of 7 scored categories. OpenWeather One Call API leads on payments & pricing.

Do Open-Meteo and OpenWeather One Call API need an API key?

Open-Meteo needs no key. OpenWeather One Call API needs an API key.

Can an agent call Open-Meteo and OpenWeather One Call API without installing anything?

Yes. Open-Meteo has a hosted endpoint at https://api.open-meteo.com/v1/forecast and OpenWeather One Call API at https://api.openweathermap.org/data/3.0/onecall.

Are Open-Meteo and OpenWeather One Call API open source?

Open-Meteo is open source (AGPL-3.0 (code), CC BY 4.0 (data)). No open-source release is listed for OpenWeather One Call API.

Other comparisons with Open-Meteo or OpenWeather One Call API

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.

Get an auditSee a sample report