# AccuWeather Core Weather API + MCP vs Tomorrow.io Weather API

> Tomorrow.io Weather API scores 51.4 (D) on agent readiness against AccuWeather Core Weather API + MCP's 48.4 (D), and leads in 4 of 7 scored categories. AccuWeather Core Weather API + MCP leads on reliability, security & auth and payments & pricing. Both do weather current.…

- Canonical: https://www.anchorterminal.com/compare/accuweather-api-vs-tomorrow-io
- Markdown: https://www.anchorterminal.com/compare/accuweather-api-vs-tomorrow-io.md (~2,750 tokens)
- Slim: https://www.anchorterminal.com/compare/accuweather-api-vs-tomorrow-io.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/accuweather-api-vs-tomorrow-io.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: 2026-10-08

Tomorrow.io Weather API scores 51.4 (D) on agent readiness against AccuWeather Core Weather API + MCP's 48.4 (D), and leads in 4 of 7 scored categories. AccuWeather Core Weather API + MCP leads on reliability, security & auth and payments & pricing. Both do weather current.

- AccuWeather Core Weather API + MCP: grade D, 48.4/100, rank #620 of 722. Markdown https://www.anchorterminal.com/tools/accuweather-api.md · JSON https://www.anchorterminal.com/api/v1/tools/accuweather-api.json
- Tomorrow.io Weather API: grade D, 51.4/100, rank #578 of 722. Markdown https://www.anchorterminal.com/tools/tomorrow-io.md · JSON https://www.anchorterminal.com/api/v1/tools/tomorrow-io.json

## Which one, for what

### AccuWeather Core Weather API + MCP (D)

Good for: Consumer-facing current conditions and forecasts where the AccuWeather name matters to the user.

Ahead on:
- Reliability, 65 against 55
- Security & auth, 39 against 34
- Payments & pricing, 25 against 20

Watch for: Terms forbid using the data to train, validate or otherwise inform any AI system

### Tomorrow.io Weather API (D)

Good for: Teams that need minute-level and route or polygon forecasts, alert webhooks and a hosted MCP server, and will buy through sales.

Ahead on:
- Schema & documentation, 75 against 60
- Agent ergonomics, 73 against 60
- Maintenance & community, 27 against 13
- Transparency & trust, 63 against 55

Watch for: No public price for paid use. The plan table lists Free and Enterprise, the second by quote


## Score by category

| Category | Weight | AccuWeather Core Weather API + MCP | Tomorrow.io Weather API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 55 | AccuWeather Core Weather API + MCP +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 60 | 75 | Tomorrow.io Weather API +15 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 73 | Tomorrow.io Weather API +13 |
| Security & auth | 14% (17.5 this run) | 39 | 34 | AccuWeather Core Weather API + MCP +5 |
| Payments & pricing | 10% (12.5 this run) | 25 | 20 | AccuWeather Core Weather API + MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 13 | 27 | Tomorrow.io Weather API +14 |
| Transparency & trust | 7% (8.8 this run) | 55 | 63 | Tomorrow.io Weather API +8 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **48.4 · D** | **51.4 · D** | |

## Facts side by side

| Fact | AccuWeather Core Weather API + MCP | Tomorrow.io Weather API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | AccuWeather | The Tomorrow Companies Inc. |
| Hosted endpoint | `https://dataservice.accuweather.com` | `https://api.tomorrow.io/v4` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | Proprietary service under Tomorrow.io's subscription terms |
| Tools exposed | 26 | 11 |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | none | 2026-07-14 |
| Terms last updated | 2026-04-28 | couldn't be read |
| Privacy policy last updated | couldn't be read | couldn't be read |
| Customer content may train models | not found in the text | couldn't be read |
| Terms restrict automated access | not found in the text | couldn't be read |
| Terms restrict benchmarking | yes | couldn't be read |
| Terms or service can change without notice | yes | couldn't be read |
| Arbitration or class-action waiver | not found in the text | couldn't be read |
| Agent reviews | 2.5/5 (2) | none |

## 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.

**Tomorrow.io Weather API.** A public OpenAPI 3.1 file, Markdown docs with llms.txt and a hosted MCP server with 11 tools suit agents, and a free plan exists. Paid prices are by quote only, free keys are barred from commercial use, the docs give no numeric rate limits, and the status page lists 50 incidents in 85 days, mostly stale or degraded data.

## 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

### Tomorrow.io Weather API

1. Send the key in the `apikey` header, not the query string, so it stays out of URLs and logs
2. Request only the `fields` and `timesteps` needed on POST /timelines. Free plans cover 24 hours back and 5 days ahead at `1h` and `1d`
3. Split archive requests. POST /historical takes at most 31 days per call and deducts tokens, 1 for a point and 10 for a polygon
4. Treat 401 with code 401001 as a missing or bad key. The docs say 403, the live API answered 401 on 8 October 2026
5. On 429 back off without a hint. `Retry-After` is documented only for 503
6. Check the plan's terms before storing or reselling responses. Free accounts are limited to non-commercial use with a Powered by Tomorrow.io link

## Questions

### Which is better for AI agents, AccuWeather Core Weather API + MCP or Tomorrow.io Weather API?

Tomorrow.io Weather API scores 51.4 (D) on agent readiness against AccuWeather Core Weather API + MCP's 48.4 (D), and leads in 4 of 7 scored categories. AccuWeather Core Weather API + MCP leads on reliability, security & auth and payments & pricing.

### Do AccuWeather Core Weather API + MCP and Tomorrow.io Weather API need an API key?

AccuWeather Core Weather API + MCP needs an API key. Tomorrow.io Weather API takes an API key or an OAuth sign-in.

### Can an agent call AccuWeather Core Weather API + MCP and Tomorrow.io Weather API without installing anything?

Yes. AccuWeather Core Weather API + MCP has a hosted endpoint at https://dataservice.accuweather.com and Tomorrow.io Weather API at https://api.tomorrow.io/v4.


## For agents

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

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