# Stormglass API vs The Weather Company Data APIs

> The Weather Company Data scores 52.6 (D) 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-weather-company
- Markdown: https://www.anchorterminal.com/compare/stormglass-vs-weather-company.md (~2,900 tokens)
- Slim: https://www.anchorterminal.com/compare/stormglass-vs-weather-company.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/stormglass-vs-weather-company.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

The Weather Company Data APIs scores 52.6 (D) on agent readiness against Stormglass API's 39.9 (E), and leads in 5 of 7 scored categories. Stormglass API leads on agent ergonomics and payments & pricing. 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
- The Weather Company Data APIs: grade D, 52.6/100, rank #734 of 950. Markdown https://www.anchorterminal.com/tools/weather-company.md · JSON https://www.anchorterminal.com/api/v1/tools/weather-company.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:
- Agent ergonomics, 65 against 54
- Payments & pricing, 25 against 20

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

### The Weather Company Data APIs (D)

Good for: A business that wants one contract for global forecasts, 4 km current conditions, alerts, imagery, aviation and deep history, and that can go through sales.

Ahead on:
- Reliability, 73 against 34
- Schema & documentation, 67 against 40
- Maintenance & community, 36 against 15

Watch for: No self-serve signup. The trial is requested through a form, is limited to enterprise customers, and the Buy now button opens a contact form.


## Score by category

| Category | Weight | Stormglass API | The Weather Company Data APIs | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 34 | 73 | The Weather Company Data APIs +39 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 40 | 67 | The Weather Company Data APIs +27 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 54 | Stormglass API +11 |
| Security & auth | 14% (17.5 this run) | 44 | 48 | The Weather Company Data APIs +4 |
| Payments & pricing | 10% (12.5 this run) | 25 | 20 | Stormglass API +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 15 | 36 | The Weather Company Data APIs +21 |
| Transparency & trust | 7% (8.8 this run) | 45 | 49 | The Weather Company Data APIs +4 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **39.9 · E** | **52.6 · D** | |

## Facts side by side

| Fact | Stormglass API | The Weather Company Data APIs |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Storm Glass AB | The Weather Company, LLC |
| Hosted endpoint | `https://api.stormglass.io/v2` | `https://api.weather.com` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Paid |
| 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. Use is under a content licensing agreement with The Weather Company, which is not published |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2026-02-26 | 2026-09-14 |
| Terms last updated | no date given | no document linked |
| Privacy policy last updated | no date given | couldn't be read |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |

## 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.

**The Weather Company Data APIs.** A wide weather data API with 168 API references built from OpenAPI documents, global 4 km current conditions, hourly history from June 2015 and a status page with component history. Keys come only through a sales-reviewed trial or contract, travel only in the URL, and the terms that govern the API are not published.

## 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

### The Weather Company Data APIs

1. Send `units`, `language` and `format=json` with a location on every v3 call, plus `Accept-Encoding: gzip`, which the usage guide marks as required.
2. Keep the key out of logs and client-side code, because it travels in the query string as `apiKey`.
3. Treat a 401 as either a bad key, an endpoint outside the key's package or an exceeded limit, and treat a 204 as no data for the query.
4. Each forecast duration (`3day` to `15day`) is a separate entitlement. Request only durations the contract covers.
5. Use `/v3/aggcommon` to combine up to 10 products in one request. Each product and each location still counts as one call.

## Questions

### Which is better for AI agents, Stormglass API or The Weather Company Data APIs?

The Weather Company Data APIs scores 52.6 (D) on agent readiness against Stormglass API's 39.9 (E), and leads in 5 of 7 scored categories. Stormglass API leads on agent ergonomics and payments & pricing.

### Do Stormglass API and The Weather Company Data APIs need an API key?

Both need an API key.

### Can an agent call Stormglass API and The Weather Company Data APIs without installing anything?

Yes. Stormglass API has a hosted endpoint at https://api.stormglass.io/v2 and The Weather Company Data APIs at https://api.weather.com.


## For agents

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

## Other comparisons with Stormglass API or The Weather Company Data APIs

- [AccuWeather Core Weather API + MCP vs The Weather Company Data APIs](https://www.anchorterminal.com/compare/accuweather-api-vs-weather-company.md)
- [Google Weather API (Maps Platform) vs The Weather Company Data APIs](https://www.anchorterminal.com/compare/google-weather-api-vs-weather-company.md)
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