# Stormglass API vs Weatherbit API

> Weatherbit scores 57.7 (C) to Stormglass's 39.9 (E) for weather forecasts. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/stormglass-vs-weatherbit
- Markdown: https://www.anchorterminal.com/compare/stormglass-vs-weatherbit.md (~2,800 tokens)
- Slim: https://www.anchorterminal.com/compare/stormglass-vs-weatherbit.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/stormglass-vs-weatherbit.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Weatherbit API scores 57.7 (C) on agent readiness against Stormglass API's 39.9 (E), and leads in 5 of 7 scored categories. Stormglass API leads on security & auth. Both do weather forecasts.

- Stormglass API: grade E, 39.9/100, rank #914 of 950. Markdown https://www.anchorterminal.com/tools/stormglass.md · JSON https://www.anchorterminal.com/api/v1/tools/stormglass.json
- Weatherbit API: grade C, 57.7/100, rank #599 of 950. Markdown https://www.anchorterminal.com/tools/weatherbit.md · JSON https://www.anchorterminal.com/api/v1/tools/weatherbit.json
- Best weather and climate data APIs for AI agents: https://www.anchorterminal.com/best/weather/index.md
- All 120 weather comparisons: https://www.anchorterminal.com/compare/weather/index.md

## Which one, for what

### Stormglass API (E)

Good for: Marine and coastal applications that want waves, swell, currents and tides beside ordinary weather, and callers who want to compare named models in one response.

Ahead on:
- Security & auth, 44 against 39

Watch for: No OpenAPI file, llms.txt, official SDK or changelog was found. The docs are eleven Markdown pages

### Weatherbit API (C)

Good for: An application that needs forecasts plus specialised datasets (air quality, lightning, soil and degree days) from one paid subscription, queried by coordinates.

Ahead on:
- Reliability, 91 against 34
- Schema & documentation, 72 against 40
- Payments & pricing, 30 against 25
- Maintenance & community, 21 against 15
- Transparency & trust, 63 against 45

Also in its favour:
- Free to start without a card

Watch for: The key is accepted only as the `key` query parameter, and the spec lists plain http as a scheme


## Score by category

| Category | Weight | Stormglass API | Weatherbit API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 34 | 91 | Weatherbit API +57 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 40 | 72 | Weatherbit API +32 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 61 | Stormglass API +4 |
| Security & auth | 14% (17.5 this run) | 44 | 39 | Stormglass API +5 |
| Payments & pricing | 10% (12.5 this run) | 25 | 30 | Weatherbit API +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 15 | 21 | Weatherbit API +6 |
| Transparency & trust | 7% (8.8 this run) | 45 | 63 | Weatherbit API +18 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **39.9 · E** | **57.7 · C** | |

## Facts side by side

| Fact | Stormglass API | Weatherbit API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Storm Glass AB | Weatherbit LLC |
| Hosted endpoint | `https://api.stormglass.io/v2` | `https://api.weatherbit.io/v2.0` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Storm Glass AB's Terms and Conditions. The Free and Small plans are not for commercial use | Proprietary service under Weatherbit's terms of service. The free plan's data is under a Creative Commons non-commercial licence. The Python SDK is MIT |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2026-02-26 | 2025-08-01 |
| Terms last updated | no date given | 2025-05-01 |
| Privacy policy last updated | no date given | 2023-12-26 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | none | 78 PyPI/wk |

## Verdicts

**Stormglass API.** 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.

**Weatherbit API.** A read-only weather API with a Swagger 2.0 spec, quota headers on every response and a status page showing 100 per cent on three API monitors over 90 days. The key travels only in the query string, the free plan allows 50 requests a day for non-commercial use, and the last dated API announcement is 1 August 2025.

## Before you call either

### Stormglass API

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

### Weatherbit API

1. Pass lat and lon. City, postal code and station lookups are accepted, but the docs recommend coordinates and mark station ID as use with caution
2. Read X-RateLimit-Remaining and X-RateLimit-Reset on each response. Daily quotas reset at 00:00 UTC and a spent quota returns 429 until then
3. Treat HTTP 204 with an empty body as no data found, not as an error
4. Split historical requests into ranges of one month or less. History needs the Plus plan or higher and has its own daily quota
5. Keep the key out of logs. It is part of the URL on every call, so always use https://api.weatherbit.io/v2.0

## Questions

### Which is better for AI agents, Stormglass API or Weatherbit API?

Weatherbit API scores 57.7 (C) on agent readiness against Stormglass API's 39.9 (E), and leads in 5 of 7 scored categories. Stormglass API leads on security & auth.

### Do Stormglass API and Weatherbit API need an API key?

Both need an API key.

### Can an agent call Stormglass API and Weatherbit API without installing anything?

Yes. Stormglass API has a hosted endpoint at https://api.stormglass.io/v2 and Weatherbit API at https://api.weatherbit.io/v2.0.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/stormglass-vs-weatherbit.json, and with the fewest tokens: https://www.anchorterminal.com/compare/stormglass-vs-weatherbit.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "stormglass", "b": "weatherbit"}`. From a terminal: `anchor compare stormglass weatherbit`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/stormglass.json and https://www.anchorterminal.com/api/v1/tools/weatherbit.json

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