National Grid ESO vs RainViewer
Same instrument, two spec sheets — measured, not claimed.
National Grid ESO vs RainViewer: common questions
Which is more reliable, National Grid ESO or RainViewer?
Both are neck-and-neck — National Grid ESO and RainViewer 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 RainViewer?
RainViewer has the lower median latency in our checks — National Grid ESO responds in 609 ms versus RainViewer at 551 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 RainViewer need an API key?
Neither needs a paid key — National Grid ESO is callable with no signup, and RainViewer is callable with no signup. Both are quick to prototype with; rate limits still apply.
Can I call National Grid ESO and RainViewer from the browser?
Yes — both National Grid ESO and RainViewer 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 RainViewer free for commercial use?
National Grid ESO has unclear commercial terms, and RainViewer 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.