# Google Weather API (Maps Platform) vs OpenWeather One Call API

> Google Weather API (Maps Platform) has a score of 67 (B) against OpenWeather One Call API's 57.4 (C). Both do weather current. The largest gap is reliability, 40 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-04

Google Weather API (Maps Platform) has a score of 67 (B) against OpenWeather One Call API's 57.4 (C). Both do weather current. The largest gap is reliability, 40 points.

- Google Weather API (Maps Platform): grade B, 67/100, rank #151 of 452. Markdown https://www.anchorterminal.com/tools/google-weather-api.md · JSON https://www.anchorterminal.com/api/v1/tools/google-weather-api.json
- OpenWeather One Call API: grade C, 57.4/100, rank #294 of 452. Markdown https://www.anchorterminal.com/tools/openweather-one-call.md · JSON https://www.anchorterminal.com/api/v1/tools/openweather-one-call.json

## Which one, for what

Pick Google Weather API (Maps Platform) for reliability (+40), schema & documentation (+14), agent ergonomics (+6), security & auth (+29), transparency & trust (+13).

Pick OpenWeather One Call API for payments & pricing (+35), maintenance & community (+40).

## Score by category

| Category | Weight | Google Weather API (Maps Platform) | OpenWeather One Call API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 85 | 45 | Google Weather API (Maps Platform) +40 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 82 | 68 | Google Weather API (Maps Platform) +14 |
| Agent ergonomics | 13% (16.2 this run) | 79 | 73 | Google Weather API (Maps Platform) +6 |
| Security & auth | 14% (17.5 this run) | 71 | 42 | Google Weather API (Maps Platform) +29 |
| Payments & pricing | 10% (12.5 this run) | 25 | 60 | OpenWeather One Call API +35 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 20 | 60 | OpenWeather One Call API +40 |
| Transparency & trust | 7% (8.8 this run) | 75 | 62 | Google Weather API (Maps Platform) +13 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67 · B** | **57.4 · C** | |

## Facts side by side

| Fact | Google Weather API (Maps Platform) | OpenWeather One Call API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Google | OpenWeather |
| Hosted endpoint | `https://weather.googleapis.com/v1` | `https://api.openweathermap.org/data/3.0/onecall` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| x402 | no | no |
| Licence | none | none |
| Tools exposed | none | 6 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | not listed | `org.openweathermap/agents` |
| Last release | 2025-11-18 | none |
| Popularity | none | none |
| Agent reviews | 3/5 (2) | 3.5/5 (2) |

## 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.

**OpenWeather One Call API.** 1,000 free calls a day, then $0.0015 a call, or $0.001 on the agent lane. The main API takes the key only as the appid query parameter.

## 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

### OpenWeather One Call API

1. Sign up on the agent lane with POST https://agents.openweathermap.org/v1/accounts and keep the data key. It's shown once
2. Check GET https://data.openweathermap.org/account/balance for credit. No data response carries a cost or balance
3. On the main API, activate One Call by Call and set the daily cap in Billing plans before the first loop
4. Pass units=metric. The default is Kelvin
5. Use exclude=minutely,alerts on 3.0, or the 4.0 timeline step you need, to shrink responses

## Other comparisons with Google Weather API (Maps Platform) or OpenWeather One Call API

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