# Xweather Weather API (slim)

> Xweather Weather API from Vaisala returns current conditions, forecasts to 15 days, history from 2004, official alerts, lightning, hail, air quality, maritime and road weather. Agents reach it as a REST API or a hosted MCP server.

- Full: https://www.anchorterminal.com/tools/xweather.md (~8,900 tokens) · this version ~2,230 tokens · JSON https://www.anchorterminal.com/tools/xweather.json · canonical https://www.anchorterminal.com/tools/xweather
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-08

**B · 67.1/100 · rank #219 of 722 · #1 in Weather & climate data · not agent-ready · confidence medium**


Assessment: A public OpenAPI file with 236 operations, a hosted MCP server in the official registry and a free tier of 15,000 accesses a month suit agents. REST credentials travel only in the query string, per-minute limits are unpublished, and the group terms bar commercial use of free plans and passing data to third parties unless a service description allows it.

## Facts

- Kind: HTTP API · vendor: Vaisala Oyj · category: Weather & climate data · legal entity: Vaisala Oyj · provenance 85/100
- Endpoint: `https://data.api.xweather.com` (HTTP)
- Auth: OAuth or key · pricing: Freemium · x402: no · licence: Proprietary service under the General Conditions of Subscription Services of Vaisala Group. The OpenAPI files and the agent skills on GitHub are MIT
- Probe metrics: not measured yet (probes haven't run)
- Surface graded: The public REST API at https://data.api.xweather.com (version 1.43.5), with the hosted MCP server at https://mcp.api.xweather.com/mcp (version 1.2.2) noted beside it
- Endpoints: OpenAPI 3.2.0 and 3.1.0 files, 58 endpoint groups, 213 paths and 236 operations (213 GET, 23 POST). Conditions, forecasts, observations, alerts, lightning, hail, air quality, maritime, tides, tropical cyclones, road weather, storm reports, normals, irradiance and places
- MCP tools: 19 documented, all named `xweather_get_*`. General 7, forecast 2, air quality 2, lightning 1, tropical 4, maps 1, road weather 2. Filters `include_tags`, `exclude_tags`, `include_tools` and `exclude_tools` on the server URL
- Forecast range: Up to 15 days, in daily, day and night, 3-hour or 1-hour intervals. Maritime forecasts reach 7 days
- History: Conditions from January 2004 to today. Archive endpoints for observations, air quality, lightning, hail, maritime and tropical cyclones, some as paid add-ons
- Credentials: `client_id` and `client_secret` per registered app, limited to a domain or app bundle namespace, sent as query parameters. MCP takes `Authorization: Bearer <client_id>_<client_secret>`, `?api_key=`, or OAuth with dynamic client registration and PKCE
- Plans: Developer, free, 15,000 accesses a month, no card, service pauses at the limit. API and Maps subscription, 1,000,000 accesses a month, shown to us as £240 a month with optional overages. Enterprise from 2 million accesses by quote
- Access cost: Accesses = endpoint multiplier × time intervals. `/impacts` 25, `/hail/threats` and `/lightning/analytics` 12, `/lightning` 10, `/airquality` 5, conditions, forecasts, alerts and observations 1. Each request inside `/batch` counts separately. 4xx and 5xx are free
- Rate limits: A per-minute limit and a per-period limit by plan. No per-minute number in the docs. `X-RateLimit-Limit-Minute`, `-Remaining-Minute`, `-Reset-Minute` and the `-Period` equivalents on responses. 429 with `maxhits_min` or `maxhits`, and `Retry-After` per the OpenAPI file
- Errors: JSON envelope `success`, `error`, `response`. 16 error codes such as `invalid_client`, `invalid_location`, `insufficient_scope` and `maxhits_min`, plus `warn_*` warnings. Application errors can arrive with HTTP 200
- Output: JSON, GeoJSON, CSV and TSV through `format`. `fields`, `limit`, `plimit`, `skip`, `pskip`, `sort`, `filter` and `query` shape the response
- Webhooks: Pushed data is a separate paid subscription arranged through sales. The agent skill says deliveries are retried two or three times with no replay
- SDKs and skills: JavaScript `@aerisweather/javascript-sdk` 1.8.6 (October 2024), iOS and Android SDKs, Python notebooks. Six agent skills under MIT in vaisala-xweather/xweather-agent-skills, release 0.15.1 on 5 October 2026
- Attribution: Required on all products. A link to https://www.xweather.com/ reading Powered by Vaisala Xweather, or the logo
- Status: status.xweather.com on Atlassian Statuspage, 21 components, among them API General, Conditions Endpoint, Forecasts Endpoint, Alerts Endpoint, Lightning Endpoints and MCP Server
- Certifications: The security page lists ISO 27001 and TISAX and says Xweather aligns with SOC 2. No report or certificate is linked

- Scores: Reliability 74, Performance pending, Schema & documentation 83, Agent ergonomics 78, Security & auth 52, Payments & pricing 32, Task success pending, Maintenance & community 81, Transparency & trust 68 · total over the 7 assessed categories
- Why: Reliability, Graded as a hosted service. · Schema & documentation, OpenAPI 3.2.0 and 3.1.0 files in vaisala-xweather/openapi under MIT, also served from GitHub Pages, with 213 paths and 236 operations. · Agent ergonomics, `fields`, `limit` and `plimit` size a REST response, and the docs give a 15-day hourly forecast as about 600 KB, or 25 KB with three fields. · Security & auth, Credentials are a `client_id` and `client_secret` per registered app, limited to a domain or app bundle namespace and regenerated in the das… · Payments & pricing, No x402, MPP or L402 in the docs, the OpenAPI file or the pricing page (0). · Maintenance & community, The newest API release is 1.43.5 on 14 September 2026, 24 days before this check (30). · Transparency & trust, Closed service under Vaisala's group subscription terms, dated 1 January 2023, which set a liability cap of twelve months' fees and ICC arbi…
- Sources: 35, open questions: 11, both in the full twin
- Capabilities: weather.current, weather.forecast, weather.historical, weather.alerts, weather.marine, data.weather
- JSON: https://www.anchorterminal.com/api/v1/tools/xweather.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/xweather.svg` or a link to https://www.anchorterminal.com/tools/xweather from a page on xweather.com or one of its subdomains, or the README of github.com/vaisala-xweather/openapi, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Check `success` and `error.code` on every response. Application errors such as `invalid_location` return HTTP 200 with `success` false
2. Send `fields`, `limit` and `plimit`. The docs put a 15-day hourly forecast at about 600 KB, and about 25 KB with three fields
3. Read `X-Cost-Tokens` after each call. Cost is the endpoint multiplier times the intervals requested, so narrow `from` and `to`
4. For MCP, send `Authorization: Bearer <client_id>_<client_secret>` and avoid the `api_key` query parameter, which puts the secret in the URL
5. Add `include_tags` or `include_tools` to the MCP URL to load only the tool groups the task needs
6. On 429 read `Retry-After` and the `X-RateLimit-Reset-*` headers. `maxhits_min` clears at the next minute, `maxhits` at the period reset

## Connect

```bash
curl 'https://data.api.xweather.com/places/98109?client_id={client_id}&client_secret={client_secret}'
```

```bash
claude mcp add --transport http xweather https://mcp.api.xweather.com/mcp --header "Authorization: Bearer CLIENT_ID_CLIENT_SECRET"
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/xweather

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| WeatherAPI.com | B | 65.3 | weather.current, weather.forecast, weather.historical, weather.alerts, weather.marine, data.weather | https://www.anchorterminal.com/tools/weatherapi-com.min.md |
| meteoblue Weather API | C | 61.7 | weather.current, weather.forecast, weather.historical, weather.alerts, weather.marine, data.weather | https://www.anchorterminal.com/tools/meteoblue.min.md |
| The Weather Company Data APIs | D | 52.6 | weather.current, weather.forecast, weather.historical, weather.alerts, weather.marine, data.weather | https://www.anchorterminal.com/tools/weather-company.min.md |
| Tomorrow.io Weather API | D | 51.4 | weather.current, weather.forecast, weather.historical, weather.alerts, weather.marine, data.weather | https://www.anchorterminal.com/tools/tomorrow-io.min.md |
| Google Weather API (Maps Platform) | B | 66.8 | weather.current, weather.forecast, weather.historical, weather.alerts, data.weather | https://www.anchorterminal.com/tools/google-weather-api.min.md |


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