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OpenWeather API (API key, free plan and One Call subscription)

Sign up for OpenWeather, verify your email, and get an API key (APPID) that activates automatically within about 2 hours. The One Call API is a separate pay-per-call subscription with 1,000 free calls per day.

Researched · not yet run liveLast researched 25 October 2026 · OpenWeather · provider site

Researched, not yet run live. Built from the provider’s official pages (linked below). A person hasn’t walked this flow end to end yet, so check each step against the source.
Do this with verapliJSON for agents

Who owns what

One OpenWeather account holds API keys, subscriptions and billing. Call limits apply to the whole account, not to each key.

  • OpenWeather account developer owned by you or your organisation
  • One Call API subscription billingoptional · under OpenWeather accountSeparate pay-per-call subscription, needs payment details [to verify exact flow].

The account must always keep at least one API key.

Have ready

  • An email address you can verify: The API key is delivered after email verification.
  • Credit/debit card or digital wallet for the One Call API subscription or a paid plan · One Call API is a separate pay-per-call subscription; OpenWeather marks it as credit card required [to verify]. [1]Needed for: Subscribe to the One Call API (optional)

Steps

Steps marked “human step” are ones only you can do: verapli never signs in, submits, pays or accepts terms for you.

  1. Create an OpenWeather account

    You sign up with your email, accept the terms and submit the form yourself.

    • Guided by hand
    • Human step: You press submit

    Where: https://home.openweathermap.org/users/sign_up

  2. Verify your email

    Click the verification link; OpenWeather then emails your API key (APPID).

    • Guided by hand
    • Human step: You sign in
    • After: Create an OpenWeather account

  3. Copy your API key

    Find the key on the API keys tab of your account (you can generate more there). Pass it as the appid parameter in every call. Wait for activation before testing.

    • verapli co-pilot
    • After: Verify your email
    The provider says
    The API key is activated automatically, up to 2 hours after successful registration. [1]

    verapli captures OPENWEATHER_API_KEY here by plain code: encrypted in your browser, never shown to AI.

    If something goes wrong (1)
    • Calls return 401 Invalid API key right after sign-up (401): The key may not be active yet; wait up to 2 hours and retry. A 401 also occurs when a free account calls data its plan does not include (e.g. 16-day forecast, history). [1]

    Where: https://home.openweathermap.org/api_keys

  4. Subscribe to the One Call API (optional)optional

    One Call API is not part of the free plan. You subscribe separately and enter payment details yourself. 1,000 calls/day are free; beyond that you pay per call. OpenWeather recommends One Call 4.0 for new integrations; 3.0 is also in the One Call API subscription.

    • Guided by hand
    • Human step: You add payment details
    • After: Copy your API key
    If something goes wrong (1)
    • One Call returns 401 although the key works for Current Weather (401): Confirm the One Call API subscription is active on the same account; activation follows payment [to verify]. [4]

    Where: https://home.openweathermap.org/subscriptions/unauth_subscribe/onecall_40/base

  5. Set a daily call cap for One Calloptional

    A default limit of 2,000 One Call calls/day is set on subscription. Lower it (e.g. to 1,000 to stay in the free allowance) in the Billing plans tab of your account. Calls over the cap return 429.

    • Guided by hand
    • After: Subscribe to the One Call API (optional)

Terms and gotchas

Plain-English summary, not legal advice. Each card links its source.

Can cost moneyThe rules say

One Call is pay-per-call and billed monthly

The One Call API subscription includes 1,000 calls/day free and charges for each call above that; the default cap is 2,000 calls/day, so you can be billed unless you lower the cap. [1]

Worth knowingThe rules say

Limits are per account, not per key

All API keys on an account share the same call limits, so extra keys do not add capacity. [2]

Worth knowingThe rules say

New keys are not instant

A new key can take up to 2 hours to activate; 401 errors in that window are expected. [1]

What you end up with

Env varSecretFormatWhat it is
OPENWEATHER_API_KEYsecret<32 hex chars>…OpenWeather API key (APPID), passed as the appid query parameter

Pricing

  • Free tier: Free plan with 60 calls/minute and 1,000,000 calls/month (current weather, 5-day/3-hour forecast, air pollution, weather maps, geocoding). One Call API gives 1,000 free calls/day within its paid subscription.
  • Costs: One Call 0.0012 GBP per call above 1,000/day. Monthly plans Startup 30 GBP, Developer 140 GBP, Professional 370 GBP.
  • Free student plan adds historical and longer forecasts; other OpenWeather pages quote One Call prices in EUR, so check the live pricing page.

Source [3]

For agents

The same entry as JSON: /api/v1/entries/openweather/api · requirements /api/v1/requirements/openweather/api · terms /api/v1/terms/openweather/api.

Remote MCP (read-only, no auth)
claude mcp add --transport http verapli https://verapli.com/mcp

> "What do I need for OpenWeather API (API key, free plan and One Call subscription), and how long will it take?"
  → tools/call requirements { "provider_id": "openweather/api" }

Sources

  1. OpenWeather – Frequently Asked Questions Key activates automatically up to 2 hours after registration; 401 while not yet active; key sent in welcome email after email verification; unlimited extra keys, account-level limits, at least one key; One Call 1,000 free calls/day, default 2,000/day limit changeable in Billing plans; cards and digital wallets accepted · accessed 25 October 2026 · official
  2. OpenWeather – How to start / API key APPID sent in confirmation email; appid parameter required on every call; keys managed on the API keys tab; free plans use api.openweathermap.org; limits apply per account not per key · accessed 25 October 2026 · official
  3. OpenWeather – Pricing Free plan 60 calls/min and 1,000,000 calls/month; student plan; Startup 30 GBP, Developer 140 GBP, Professional 370 GBP per month; One Call first 1,000 calls/day free then 0.0012 GBP per call · accessed 25 October 2026 · official
  4. OpenWeather – One Call API 3.0 One Call 3.0 included only in the separate "One Call API" subscription with 1,000 calls/day free and pay per call beyond; 429 when quota exceeded; One Call 4.0 recommended for new integrations · accessed 25 October 2026 · official
  5. OpenWeather – Migration guide from AccuWeather API Comparison table with "Credit card required" row for the One Call API subscription versus Free subscription "activated upon receiving an API key" (column mapping unclear in fetch) · accessed 25 October 2026 · official

Provider rules change. This page is generated from verapli registry version 2026.1025.316; spotted something out of date? Tell us. OpenWeather is not affiliated with verapli.