shipapis
StarSubmit an APISubmit API

National Grid ESO vs Weather Underground API

Same instrument, two spec sheets — measured, not claimed.

APINational Grid ESOHEALTHY92Weather Underground APIREACHABLE100
Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms609104
P95 · ms13111117
AuthnoneapiKey
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseNESO Open Data Licence (OGL-based); varies per datasetUnverified
Free tierFree — limits not publishedFree tier — API key may be required for production
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

National Grid ESO vs Weather Underground API: common questions

Which is more reliable, National Grid ESO or Weather Underground API?

Both are neck-and-neck — National Grid ESO and Weather Underground API each measure 100% uptime over 90 days on our probe schedule. Reliability here is verified from our own scheduled checks; use the 30-day bars above to see which has been steadier lately.

Which is faster, National Grid ESO or Weather Underground API?

Weather Underground API has the lower median latency in our checks — National Grid ESO responds in 609 ms versus Weather Underground API at 104 ms (P50). Tail latency (P95) is in the table above; for most workloads the median is the number that shapes how the API feels.

Do National Grid ESO and Weather Underground API need an API key?

National Grid ESO needs no key, while Weather Underground API requires a free API key. If you want to start calling without signup, reach for National Grid ESO first.

Can I call National Grid ESO and Weather Underground API from the browser?

Yes — both National Grid ESO and Weather Underground API send CORS headers over HTTPS, so front-end code can fetch either directly with no backend proxy. That makes them easy to swap in a client-side app while you compare responses.

Are National Grid ESO and Weather Underground API free for commercial use?

National Grid ESO has unclear commercial terms, and Weather Underground API has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.