An independent comparison of the weather models every forecast is built on, graded against what the weather actually did.
Every weather app you use is a presentation layer over a small number of numerical models. checkweather.io shows those models side by side for any town in the United States, United Kingdom, Canada, Australia and New Zealand, so you can see where they agree and where they split. Where they split, the forecast is genuinely uncertain, and no single blended number will tell you that.
We also grade them. For each city we take each model's archived forecast and compare it against ERA5, the European Centre's reanalysis of the weather that actually happened, over a rolling 30 days. That produces the CheckWeather Score, and it is measured rather than argued. The full method, including what it favours and what it cannot do, is on the methodology page.
checkweather.io is published by Nortra Online ApS (CVR DK43186388), 2800 Kongens Lyngby, Denmark. We have no affiliation with any national weather service or consumer weather brand, and we do not take payment to rank or recommend any provider.
Forecasts and reanalysis are sourced via Open-Meteo under CC BY 4.0, which serves the national and global models: NWS/NOAA, ECMWF, the UK Met Office, Environment Canada, DWD ICON and MET Norway. Rain radar tiles come from RainViewer. Closed consumer blends such as AccuWeather, The Weather Channel and BBC Weather cannot be independently verified, so we grade the open models they are built on and say so.
ERA5 is produced by the same centre that runs the European model, so that model carries a small structural advantage in our scoring. Thirty days measures current form, not all-time skill. We publish both caveats on every scoreboard rather than bury them.
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