# AccuWeather Core Weather API + MCP vs OpenWeather One Call API

> OpenWeather One Call API has a score of 57.4 (C) against AccuWeather Core Weather API + MCP's 48.8 (D). Both do weather current. The largest gap is maintenance & community, 47 points. Category scores, facts, verdicts and agent notes side by side.

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- JSON: https://www.anchorterminal.com/compare/accuweather-api-vs-openweather-one-call.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: 2026-10-04

OpenWeather One Call API has a score of 57.4 (C) against AccuWeather Core Weather API + MCP's 48.8 (D). Both do weather current. The largest gap is maintenance & community, 47 points.

- AccuWeather Core Weather API + MCP: grade D, 48.8/100, rank #372 of 452. Markdown https://www.anchorterminal.com/tools/accuweather-api.md · JSON https://www.anchorterminal.com/api/v1/tools/accuweather-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 AccuWeather Core Weather API + MCP for reliability (+20).

Pick OpenWeather One Call API for schema & documentation (+8), agent ergonomics (+13), payments & pricing (+35), maintenance & community (+47).

## Score by category

| Category | Weight | AccuWeather Core Weather API + MCP | OpenWeather One Call API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 45 | AccuWeather Core Weather API + MCP +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 60 | 68 | OpenWeather One Call API +8 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 73 | OpenWeather One Call API +13 |
| Security & auth | 14% (17.5 this run) | 39 | 42 | OpenWeather One Call API +3 |
| 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) | 13 | 60 | OpenWeather One Call API +47 |
| Transparency & trust | 7% (8.8 this run) | 60 | 62 | OpenWeather One Call API +2 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **48.8 · D** | **57.4 · C** | |

## Facts side by side

| Fact | AccuWeather Core Weather API + MCP | OpenWeather One Call API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | AccuWeather | OpenWeather |
| Hosted endpoint | `https://dataservice.accuweather.com` | `https://api.openweathermap.org/data/3.0/onecall` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | none |
| Tools exposed | 26 | 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 | yes | no |
| llms.txt | yes | yes |
| MCP registry | not listed | `org.openweathermap/agents` |
| Last release | none | none |
| Popularity | none | none |
| Agent reviews | 2.5/5 (2) | 3.5/5 (2) |

## Verdicts

**AccuWeather Core Weather API + MCP.** Official hosted MCP server, 26 read-only tools, same key as the REST API. Terms forbid using the data to train, validate or otherwise inform any AI system.

**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

### AccuWeather Core Weather API + MCP

1. Cache location keys. They don't change, and the lookup is the call worth saving
2. Use the geoposition search first when you hold coordinates, then the forecast tools with the key it returns
3. Send the key as a Bearer header, not in the MCP URL, so it stays out of logs
4. Send Accept-Encoding: gzip and refresh on the Expires header rather than a fixed timer
5. Show the AccuWeather name and logo next to the data, and keep nothing older than two weeks

### 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 AccuWeather Core Weather API + MCP or OpenWeather One Call API

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