# Stormglass API (slim)

> Weather and marine data API from Storm Glass AB of Sweden. It returns hourly forecasts, ERA5 history from 2014, tides, solar, soil and ocean parameters by coordinates, per source or blended, over HTTPS with an API key.

- Full: https://www.anchorterminal.com/tools/stormglass.md (~7,050 tokens) · this version ~1,730 tokens · JSON https://www.anchorterminal.com/tools/stormglass.json · canonical https://www.anchorterminal.com/tools/stormglass
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-10

**E · 39.9/100 · rank #914 of 950 · #15 in Weather & climate data · not agent-ready · confidence medium**


Assessment: A read-only weather and marine API with about 70 hourly parameters, per-source values from named national models, tide data and ERA5 history from 2014. No OpenAPI file, status page, SDK or security page was found, the free plan allows 10 requests a day, and the docs and FAQ disagree on the status code for a spent quota.

## Facts

- Kind: HTTP API · vendor: Storm Glass AB · category: Weather & climate data · legal entity: Storm Glass AB · provenance 68/100
- Endpoint: `https://api.stormglass.io/v2` (HTTP)
- Auth: API key · pricing: Freemium · x402: no · licence: Proprietary service under Storm Glass AB's Terms and Conditions. The Free and Small plans are not for commercial use
- Probe metrics: not measured yet (probes haven't run)
- Endpoints: Ten GET paths under https://api.stormglass.io/v2. `/weather/point`, `/historical/point`, `/bio/point`, `/solar/point`, `/astronomy/point`, `/elevation/point`, `/tide/extremes/point`, `/tide/sea-level/point`, `/tide/stations` and `/tide/stations/area`
- Free plan: 10 requests a day with all parameters, non-commercial, no support. The terms call it an evaluation plan. Whether signup asks for a card was not established
- Forecast range: Hourly, 240 hours for the blended `sg` source, 360 hours for ECMWF AIFS and NOAA AIGFS, and 48 to 240 hours for the other named sources, per the sources page. Tide and astronomy calls default to 10 days
- History: ERA5 from 1 January 2014, hourly at 0.25 degrees (0.5 for waves), at most 10 days a call, with the last 7 days or so missing. `/weather/point` keeps forecast records for 14 days back
- Marine data: Wave, swell, secondary swell and wind wave height, direction and period, current speed and direction, water temperature, sea ice, sea level, tide extremes and bathymetry. `/bio/point` adds chlorophyll, salinity, pH, oxygen and phytoplankton
- Rate limits: Daily request quota by plan (10, 500, 5,000 or 25,000). No per-second limit is documented. `meta.dailyQuota` and `meta.requestCount` on every response
- Errors: 402 quota spent, 403 key missing or malformed, 404, 405, 410 legacy resource, 422 bad parameters, 503 try again later. The body seen for 403 was `{"errors":{"key":"API key is invalid"}}`
- Plan prices: Small 19 euros, Medium 49 euros and Large 129 euros a month, 10 per cent off when billed annually. Custom enterprise plans by email. No overage price
- Sources: ECMWF (oper, wave, ERA5, AIFS), NOAA (GFS, GFS-Wave, AIGFS), Météo-France, DWD, UK Met Office, MET Norway, FCOO, FMI and CMEMS, each selectable with `source`
- SDK: None official. Request examples in the docs for Python, curl and JavaScript
- Data kept: Account information is stored until the account is deleted, by email to support. No retention period for request data is stated. HubSpot is the one third party named

- Scores: Reliability 34, Performance pending, Schema & documentation 40, Agent ergonomics 65, Security & auth 44, Payments & pricing 25, Task success pending, Maintenance & community 15, Transparency & trust 45 · total over the 7 assessed categories
- Why: Reliability, Graded as a hosted service. · Schema & documentation, No OpenAPI file or other machine-readable contract was found in the docs (0 of 25). · Agent ergonomics, This is an API with no MCP server. · Security & auth, One plain key per account, sent in the `Authorization` header and never in the URL. · Payments & pricing, No x402, MPP or L402. The API's 402 means a spent quota (0). · Maintenance & community, The latest dated announcement is the ERA5 blog post of 26 February 2026, 225 days before this check. · Transparency & trust, Closed service with one short terms page, dated 17 March 2026. The FAQ limits commercial use to Medium and higher.
- Sources: 18, open questions: 9, both in the full twin
- Capabilities: weather.forecast, weather.marine, weather.historical, data.weather
- JSON: https://www.anchorterminal.com/api/v1/tools/stormglass.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/stormglass.svg` or a link to https://www.anchorterminal.com/tools/stormglass from a page on stormglass.io or one of its subdomains, 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. Send the key as `Authorization: KEY` with no Bearer prefix. A missing or wrong key returns 403 with `{"errors":{"key":"API key is invalid"}}`
2. Always pass `source=sg` or a short source list on `/weather/point`. The default is every source, which multiplies the size of each hourly record
3. Treat 402 as a spent daily quota, not a billing failure, and stop until the next day. Read `meta.requestCount` against `meta.dailyQuota` on each response
4. Use `/historical/point` for past dates, at most 10 days a call and nothing newer than about 7 days. `/weather/point` looks back 14 days only
5. Send and read all times in UTC. Tide sea levels are relative to the chosen datum (MSL by default) and are not water depth

## Connect

```bash
curl -H "Authorization: API_KEY" "https://api.stormglass.io/v2/weather/point?lat=58.7984&lng=17.8081&params=waveHeight,airTemperature&source=sg"
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/stormglass

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## Panel reviews (0, desk reviews from public material, no calls made)