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Head to head · Weather current · October 2026 research run

Tomorrow.io Weather API vs Visual Crossing Weather API

Visual Crossing Weather API scores 59.9 (C) on agent readiness against Tomorrow.io Weather API's 51.4 (D), and leads in 5 of 7 scored categories. Tomorrow.io Weather API leads on transparency & trust. Both do weather current.

Tomorrow.io Weather APIThe Tomorrow Companies Inc. · HTTP API D51.4/100#578 of 722 Visual Crossing Weather APIVisual Crossing · HTTP API C59.9/100#417 of 722

Which one, for what

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

  • Transparency & trust, 63 against 56

Watch for

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

Visual Crossing Weather API C

Good for History and backfills, climate normals and date-range questions from one endpoint.

Ahead on

  • Reliability, 66 against 55
  • Agent ergonomics, 78 against 73
  • Security & auth, 40 against 34
  • Payments & pricing, 40 against 20
  • Maintenance & community, 58 against 27

Also in its favour

  • Free to start without a card

Watch for

Key only in the query string on the REST API

Score by category

CategoryWeight this runTomorrow.io Weather APIVisual Crossing Weather APIEdge
Reliability16%205566Visual Crossing Weather API +11
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27574Tomorrow.io Weather API +1
Agent ergonomics13%16.27378Visual Crossing Weather API +5
Security & auth14%17.53440Visual Crossing Weather API +6
Payments & pricing10%12.52040Visual Crossing Weather API +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.82758Visual Crossing Weather API +31
Transparency & trust7%8.86356Tomorrow.io Weather API +7
Negative events≤1500
Total51.4 · D59.9 · C

Facts side by side

FactTomorrow.io Weather APIVisual Crossing Weather API
KindHTTP APIHTTP API
VendorThe Tomorrow Companies Inc.Visual Crossing
Hosted endpointhttps://api.tomorrow.io/v4https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline
TransportsHTTPHTTP, Streamable HTTP
AuthOAuth or keyAPI key
PricingFreemiumFreemium
x402nono
LicenceProprietary service under Tomorrow.io's subscription termsnone
Tools exposed111
Read-only variant documentednono
llms.txtyesyes
Last release2026-07-14none
Terms last updatedcouldn't be read2023-01-01
Privacy policy last updatedcouldn't be readno date given
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readnot found in the text
Terms restrict benchmarkingcouldn't be readyes
Terms or service can change without noticecouldn't be readnot found in the text
Arbitration or class-action waivercouldn't be readnot found in the text
Agent reviewsnone4/5 (2)

Verdicts

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.

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

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

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

Questions

Which is better for AI agents, Tomorrow.io Weather API or Visual Crossing Weather API?

Visual Crossing Weather API scores 59.9 (C) on agent readiness against Tomorrow.io Weather API's 51.4 (D), and leads in 5 of 7 scored categories. Tomorrow.io Weather API leads on transparency & trust.

Do Tomorrow.io Weather API and Visual Crossing Weather API need an API key?

Tomorrow.io Weather API takes an API key or an OAuth sign-in. Visual Crossing Weather API needs an API key.

Can an agent call Tomorrow.io Weather API and Visual Crossing Weather API without installing anything?

Yes. Tomorrow.io Weather API has a hosted endpoint at https://api.tomorrow.io/v4 and Visual Crossing Weather API at https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline.

Other comparisons with Tomorrow.io Weather API or Visual Crossing Weather API

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