Over 5000 U.S. Weather Stations
Ground stations measure solar and weather data (i.e. temp, humidity, wind speed, evapotranspiration, soil temp). Some sensors aren't available on all stations. 

Quality Control
We use statistical quality control procedures to mark faulty data. Errors may exist as in any large dataset.
We avoid private and coop stations for accuracy.  Our quality control process has several layers, including solar envelopes and nearby station comparisons.

Raw Data
Data is gathered weekly from thousands of US stations (dozens of networks) and rationalized into a single database. We collect international and hourly data separately, mostly upon request.

Compare our data to others

You can read more about our data at