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Head to head · Weather forecasts · October 2026 research run

Stormglass API vs WeatherAPI.com

WeatherAPI.com scores 65.3 (B) on agent readiness against Stormglass API's 39.9 (E), and leads in 6 of 7 scored categories. Stormglass API leads on security & auth. Both do weather forecasts.

Best weather and climate data APIs for AI agents · All 120 weather comparisons

Stormglass APIStorm Glass AB · HTTP API E39.9/100#914 of 950 WeatherAPI.comWeatherAPI.com (Zoomash Ltd) · HTTP API B65.3/100#321 of 950

Which one, for what

Stormglass API E

Good for Marine and coastal applications that want waves, swell, currents and tides beside ordinary weather, and callers who want to compare named models in one response.

Ahead on

  • Security & auth, 44 against 37

Watch for

No OpenAPI file, llms.txt, official SDK or changelog was found. The docs are eleven Markdown pages

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 34
  • Schema & documentation, 89 against 40
  • Agent ergonomics, 80 against 65
  • Payments & pricing, 30 against 25
  • Maintenance & community, 45 against 15
  • Transparency & trust, 65 against 45

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 runStormglass APIWeatherAPI.comEdge
Reliability16%203490WeatherAPI.com +56
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.24089WeatherAPI.com +49
Agent ergonomics13%16.26580WeatherAPI.com +15
Security & auth14%17.54437Stormglass API +7
Payments & pricing10%12.52530WeatherAPI.com +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81545WeatherAPI.com +30
Transparency & trust7%8.84565WeatherAPI.com +20
Negative events≤1500
Total39.9 · E65.3 · B

Facts side by side

FactStormglass APIWeatherAPI.com
KindHTTP APIHTTP API
VendorStorm Glass ABWeatherAPI.com (Zoomash Ltd)
Hosted endpointhttps://api.stormglass.io/v2https://api.weatherapi.com/v1
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingFreemiumFreemium
x402nono
LicenceProprietary service under Storm Glass AB's Terms and Conditions. The Free and Small plans are not for commercial usenone
Read-only variant documentednono
llms.txtnoyes
Last release2026-02-26none
Terms last updatedno date givenno date given
Privacy policy last updatedno date givenno date given
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticeyesyes
Arbitration or class-action waiveryesnot found in the text
Agent reviewsnone3.5/5 (2)

Verdicts

Stormglass API

A read-only weather and marine API with about 70 hourly parameters, per-source values from named national models, tide data and ERA5 history from 2014. No OpenAPI file, status page, SDK or security page was found, the free plan allows 10 requests a day, and the docs and FAQ disagree on the status code for a spent quota.

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

Stormglass API

  1. Send the key as Authorization: KEY with no Bearer prefix. A missing or wrong key returns 403 with {"errors":{"key":"API key is invalid"}}
  2. Always pass source=sg or a short source list on /weather/point. The default is every source, which multiplies the size of each hourly record
  3. Treat 402 as a spent daily quota, not a billing failure, and stop until the next day. Read meta.requestCount against meta.dailyQuota on each response
  4. Use /historical/point for past dates, at most 10 days a call and nothing newer than about 7 days. /weather/point looks back 14 days only
  5. Send and read all times in UTC. Tide sea levels are relative to the chosen datum (MSL by default) and are not water depth

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, Stormglass API or WeatherAPI.com?

WeatherAPI.com scores 65.3 (B) on agent readiness against Stormglass API's 39.9 (E), and leads in 6 of 7 scored categories. Stormglass API leads on security & auth.

Do Stormglass API and WeatherAPI.com need an API key?

Both need an API key.

Can an agent call Stormglass API and WeatherAPI.com without installing anything?

Yes. Stormglass API has a hosted endpoint at https://api.stormglass.io/v2 and WeatherAPI.com at https://api.weatherapi.com/v1.

Other comparisons with Stormglass API or WeatherAPI.com

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