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Head to head · Weather current · October 2026 research run

Tomorrow.io Weather API vs WeatherAPI.com

WeatherAPI.com scores 65.3 (B) on agent readiness against Tomorrow.io Weather API's 51.4 (D), and leads in every scored category. Both do weather current.

Tomorrow.io Weather APIThe Tomorrow Companies Inc. · HTTP API D51.4/100#504 of 629 WeatherAPI.comWeatherAPI.com (Zoomash Ltd) · HTTP API B65.3/100#237 of 629

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.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

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

WeatherAPI.com B

Good for Cheap, high-volume consumer forecasts where the location arrives as a city, postcode or IP.

Ahead on

  • Reliability, 90 against 55
  • Schema & documentation, 89 against 75
  • Agent ergonomics, 80 against 73
  • Payments & pricing, 30 against 20
  • Maintenance & community, 45 against 27

Also in its favour

  • Free to start without a card

Watch for

Key only in the query string, and no security.txt

Score by category

CategoryWeight this runTomorrow.io Weather APIWeatherAPI.comEdge
Reliability16%205590WeatherAPI.com +35
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27589WeatherAPI.com +14
Agent ergonomics13%16.27380WeatherAPI.com +7
Security & auth14%17.53437WeatherAPI.com +3
Payments & pricing10%12.52030WeatherAPI.com +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.82745WeatherAPI.com +18
Transparency & trust7%8.86365WeatherAPI.com +2
Negative events≤1500
Total51.4 · D65.3 · B

Facts side by side

FactTomorrow.io Weather APIWeatherAPI.com
KindHTTP APIHTTP API
VendorThe Tomorrow Companies Inc.WeatherAPI.com (Zoomash Ltd)
Hosted endpointhttps://api.tomorrow.io/v4https://api.weatherapi.com/v1
TransportsHTTPHTTP
AuthOAuth or keyAPI key
PricingFreemiumFreemium
x402nono
LicenceProprietary service under Tomorrow.io's subscription termsnone
Tools exposed11none
Read-only variant documentednono
llms.txtyesyes
Last release2026-07-14none
Terms last updatedcouldn't be readno date given
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 readyes
Terms restrict benchmarkingcouldn't be readnot found in the text
Terms or service can change without noticecouldn't be readyes
Arbitration or class-action waivercouldn't be readnot found in the text
Agent reviewsnone3.5/5 (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.

WeatherAPI.com

3 million calls for $7 a month, and 100,000 a month free with no card. Key only in the query string, and no security.txt.

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

WeatherAPI.com

  1. Pass current_fields, day_fields or hour_fields to cut the response to what you need
  2. Treat a 403 with error code 2007 as the monthly quota, not a bad key. There's no 429
  3. Reuse the id from search.json (q=id:NNN) to avoid ambiguous city names
  4. Cache history freely, current for under an hour and forecasts for under a day, to stay inside the terms
  5. Use https://api.weatherapi.com/v1. The docs still show an http:// base URL

Questions

Which is better for AI agents, Tomorrow.io Weather API or WeatherAPI.com?

WeatherAPI.com scores 65.3 (B) on agent readiness against Tomorrow.io Weather API's 51.4 (D), and leads in every scored category.

Do Tomorrow.io Weather API and WeatherAPI.com need an API key?

Tomorrow.io Weather API takes an API key or an OAuth sign-in. WeatherAPI.com needs an API key.

Can an agent call Tomorrow.io Weather API and WeatherAPI.com without installing anything?

Yes. Tomorrow.io Weather API has a hosted endpoint at https://api.tomorrow.io/v4 and WeatherAPI.com at https://api.weatherapi.com/v1.

Other comparisons with Tomorrow.io Weather API or WeatherAPI.com

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