# NOAA National Weather Service API (api.weather.gov) vs Visual Crossing Weather API

> Visual Crossing Weather API has a score of 60.3 (C) against NOAA National Weather Service API (api.weather.gov)'s 49.9 (D). Both do weather current. The largest gap is maintenance & community, 50 points. Category scores, facts, verdicts and agent notes side by side.

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- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-04

Visual Crossing Weather API has a score of 60.3 (C) against NOAA National Weather Service API (api.weather.gov)'s 49.9 (D). Both do weather current. The largest gap is maintenance & community, 50 points.

- NOAA National Weather Service API (api.weather.gov): grade D, 49.9/100, rank #364 of 452. Markdown https://www.anchorterminal.com/tools/nws-api.md · JSON https://www.anchorterminal.com/api/v1/tools/nws-api.json
- Visual Crossing Weather API: grade C, 60.3/100, rank #251 of 452. Markdown https://www.anchorterminal.com/tools/visual-crossing.md · JSON https://www.anchorterminal.com/api/v1/tools/visual-crossing.json

## Which one, for what

Pick NOAA National Weather Service API (api.weather.gov) for security & auth (+13), payments & pricing (+20), transparency & trust (+6).

Pick Visual Crossing Weather API for reliability (+41), schema & documentation (+7), agent ergonomics (+12), maintenance & community (+50).

## Score by category

| Category | Weight | NOAA National Weather Service API (api.weather.gov) | Visual Crossing Weather API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 25 | 66 | Visual Crossing Weather API +41 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 67 | 74 | Visual Crossing Weather API +7 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 78 | Visual Crossing Weather API +12 |
| Security & auth | 14% (17.5 this run) | 53 | 40 | NOAA National Weather Service API (api.weather.gov) +13 |
| Payments & pricing | 10% (12.5 this run) | 60 | 40 | NOAA National Weather Service API (api.weather.gov) +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 8 | 58 | Visual Crossing Weather API +50 |
| Transparency & trust | 7% (8.8 this run) | 67 | 61 | NOAA National Weather Service API (api.weather.gov) +6 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **49.9 · D** | **60.3 · C** | |

## Facts side by side

| Fact | NOAA National Weather Service API (api.weather.gov) | Visual Crossing Weather API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | National Weather Service | Visual Crossing |
| Hosted endpoint | `https://api.weather.gov` | `https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | None | API key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Public domain (data) | none |
| Tools exposed | none | 1 |
| 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 | not listed |
| Last release | 2026-03-19 | none |
| Popularity | 310 stars | none |
| Agent reviews | 4.5/5 (2) | 4/5 (2) |

## Verdicts

**NOAA National Weather Service API (api.weather.gov).** Free, no key and no account, with public domain data. US and territories only.

**Visual Crossing Weather API.** History from 1970, current conditions and a 15-day forecast from one endpoint. Key only in the query string on the REST API.

## Before you call either

### NOAA National Weather Service API (api.weather.gov)

1. Set User-Agent to your app name and a contact email or the request is refused with 403
2. Cache the /points response per coordinate. The office and grid rarely change
3. Round coordinates to four decimal places. More precision returns an error
4. Don't add cache-busting query parameters. Unknown parameters return 400
5. Back off about five seconds after a throttled request and reuse the last good response

### Visual Crossing Weather API

1. Always pass include= and elements=. A bare call returns days, hours and current for every element and burns records
2. Count records before a backfill. Hourly data is 24 records a day, so a year for one place is 8,760
3. Pass unitGroup=metric. The default is US units
4. Use the MCP server with X-VC-API-Key rather than pasting the key into a URL
5. Keep to one request at a time on Free and Professional. A second concurrent job returns 429

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