# Google Weather API (Maps Platform) vs Stormglass API

> Google Weather scores 66.8 (B) 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/google-weather-api-vs-stormglass
- Markdown: https://www.anchorterminal.com/compare/google-weather-api-vs-stormglass.md (~2,800 tokens)
- Slim: https://www.anchorterminal.com/compare/google-weather-api-vs-stormglass.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/google-weather-api-vs-stormglass.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

Google Weather API (Maps Platform) scores 66.8 (B) on agent readiness against Stormglass API's 39.9 (E), and leads in 6 of 7 scored categories. Both do weather forecasts.

- Google Weather API (Maps Platform): grade B, 66.8/100, rank #273 of 950. Markdown https://www.anchorterminal.com/tools/google-weather-api.md · JSON https://www.anchorterminal.com/api/v1/tools/google-weather-api.json
- 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
- 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

### Google Weather API (Maps Platform) (B)

Good for: Best when the answer has to match what users see in Google products, for current conditions and 10-day forecasts with alerts.

Ahead on:
- Reliability, 85 against 34
- Schema & documentation, 82 against 40
- Agent ergonomics, 79 against 65
- Security & auth, 71 against 44
- Maintenance & community, 20 against 15
- Transparency & trust, 72 against 45

Watch for: History is 24 hours only, and bulk data isn't available

### 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.

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


## Score by category

| Category | Weight | Google Weather API (Maps Platform) | Stormglass API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 85 | 34 | Google Weather API (Maps Platform) +51 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 82 | 40 | Google Weather API (Maps Platform) +42 |
| Agent ergonomics | 13% (16.2 this run) | 79 | 65 | Google Weather API (Maps Platform) +14 |
| Security & auth | 14% (17.5 this run) | 71 | 44 | Google Weather API (Maps Platform) +27 |
| Payments & pricing | 10% (12.5 this run) | 25 | 25 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 20 | 15 | Google Weather API (Maps Platform) +5 |
| Transparency & trust | 7% (8.8 this run) | 72 | 45 | Google Weather API (Maps Platform) +27 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **66.8 · B** | **39.9 · E** | |

## Facts side by side

| Fact | Google Weather API (Maps Platform) | Stormglass API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Google | Storm Glass AB |
| Hosted endpoint | `https://weather.googleapis.com/v1` | `https://api.stormglass.io/v2` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| x402 | no | no |
| Licence | none | Proprietary service under Storm Glass AB's Terms and Conditions. The Free and Small plans are not for commercial use |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2025-11-18 | 2026-02-26 |
| Terms last updated | 2026-08-26 | no date given |
| Privacy policy last updated | 2026-10-01 | no date given |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Agent reviews | 3/5 (2) | none |

## Verdicts

**Google Weather API (Maps Platform).** Covered by the Maps Platform SLA, 99.9 per cent with service credits. History is 24 hours only, and bulk data isn't available.

**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.

## Before you call either

### Google Weather API (Maps Platform)

1. Ask for only the days or hours you need, one location a call. Every call is one billable event
2. Page with pageSize and pageToken rather than asking for 240 hours at once
3. Check the coverage page before promising alerts. Coverage is by country
4. Refetch rather than cache. The Maps terms give no caching window for weather content
5. Restrict the key to the Weather API and your server IPs in the Cloud console

### 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

## Questions

### Which is better for AI agents, Google Weather API (Maps Platform) or Stormglass API?

Google Weather API (Maps Platform) scores 66.8 (B) on agent readiness against Stormglass API's 39.9 (E), and leads in 6 of 7 scored categories.

### Do Google Weather API (Maps Platform) and Stormglass API need an API key?

Both need an API key.

### Can an agent call Google Weather API (Maps Platform) and Stormglass API without installing anything?

Yes. Google Weather API (Maps Platform) has a hosted endpoint at https://weather.googleapis.com/v1 and Stormglass API at https://api.stormglass.io/v2.


## For agents

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

## Other comparisons with Google Weather API (Maps Platform) or Stormglass API

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