How RainAtlas works
Latest radar image : 15:30 UTC · models : ICON-D2 12Z, ICON-EU 12Z, GFS 06Z
Official weather radars, rebuilt every 10 minutes
RainAtlas does not copy another weather app. Every 10 minutes our servers download the latest images of three open radar networks and merge them into one map: the EUMETNET OPERA composite (radars of 24 European countries, including the United Kingdom, France, Spain, the Benelux, Scandinavia and Poland), the composite of the German weather service DWD (Germany and about 150 km around it) and NOAA MRMS (the contiguous United States). Where two networks overlap we keep the stronger echo. The map keeps the last two hours.
How the next hour is computed
For a point, we read the radar reflectivity in a window of about 5 km around it and convert it to a rain rate with the Marshall-Palmer relation. We count it as rain from 15 dBZ, about 0.3 mm per hour. In Germany and around it, the DWD publishes its own radar forecast up to two hours ahead: we use it directly. Elsewhere in radar coverage we compare the last two images, measure how the rain moved (phase correlation over about 200 km) and extend that movement for 60 minutes. The answer lists the rain rate every 10 minutes, when the rain should start or stop, and which method was used.
Outside radar coverage
Where no open radar exists yet, the next-hour answer and the map come from our hour-by-hour rain forecast: ICON-D2 (DWD, 2.2 km) over central Europe, ICON-EU (DWD, 7 km) over Europe and GFS (NOAA, 0.25°) everywhere else. Pages say clearly when the answer comes from a forecast instead of a radar.
Hour by hour and 14 days
The hourly rain for the next 12 hours uses the same models as above, refreshed with each new run. The 14-day outlook comes from our multi-model engine (ECMWF-AIFS, NOAA GFS, DWD ICON): daily totals, estimated hours of rain and storm risk. Beyond 10 days the outlook is a trend.
Rain climate
Monthly rain normals come from the Copernicus ERA5 reanalysis, averaged over 1991–2020 for each city.
Sources and licences
EUMETNET OPERA radar composite (CC BY 4.0) · Deutscher Wetterdienst radar and ICON models (CC BY 4.0) · NOAA MRMS and GFS (public domain) · ECMWF open data (CC BY 4.0) · Copernicus ERA5. All allow commercial reuse with attribution.