ERA5 is the most widely used climate reanalysis dataset in the world, and for good reason: it provides a physically consistent, gap-free record of the global atmosphere, land surface, and ocean from 1940 to the present at hourly resolution.
Produced by ECMWF under the Copernicus Climate Change Service, ERA5 fuses billions of historical observations from weather stations, satellites, buoys, and aircraft with a state-of-the-art atmospheric model — producing a gridded dataset where every variable at every point in time is internally consistent. This makes it fundamentally different from station-based records or satellite-only products, which inevitably have spatial gaps and temporal discontinuities.
ERA5's strength is the combination of temporal depth, hourly granularity, and variable breadth — hundreds of parameters spanning temperature, wind, precipitation, radiation, soil moisture, snow, and ocean waves. That range makes it the default climate input for renewable energy resource assessment, agricultural modeling, hydrological simulation, insurance risk analytics, and long-term climate trend analysis.
Datasets like WorldClim and CHELSA offer finer spatial resolution, but only as monthly or annual summaries; ERA5 gives you the hourly signal needed for wind power modeling, extreme event analysis, and diurnal cycle studies. For land-focused work requiring higher spatial detail, ERA5-Land provides a 9km companion dataset with the same temporal coverage.
