All climate scores are built on three complementary satellite datasets. Each covers a different aspect of weather, and together they give us global, hourly, decade-long climate baselines for every city.
ERA5 — the backbone
ECMWF's ERA5 is the world's most comprehensive climate reanalysis. Hourly weather data on a 0.25° grid, going back to 1940. We use the 2015–2024 window to compute temperature, UTCI, humidity, wind, radiation, and sunshine for every city.
ERA5 is the state of the art for global climate baselines — used by meteorological agencies worldwide.
CHIRPS — rainfall correction
Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) combines satellite observations with ground rain gauges. We use it to correct ERA5 precipitation, which underestimates rainfall extremes in tropical and mountainous regions.
NASA POWER — solar cross-check
NASA's Prediction Of Worldwide Energy Resources provides solar radiation, surface temperature, and meteorology from satellite observations. We cross-check ERA5 against POWER for solar and temperature metrics, especially in regions with sparse ground weather stations.
Why three sources instead of one
No single dataset is perfect everywhere. ERA5 is comprehensive but can miss localized rainfall. CHIRPS fills that gap for precipitation. POWER provides an independent solar radiation measurement. Cross-referencing gives us higher confidence scores.
See it in action
Every climate metric on a city page cites its source dataset. The explore map climate filters are all powered by this pipeline.