From the Solar Time Series Download panel, a user can choose which dataset(s) to download and the type of data file they want. To learn more about each irradiance dataset, see their FAQ entries: Vaisala 1.0, Vaisala 1.1 Vaisala 1.2, Vaisala 2.0, Vaisala 2.1.
Weather parameters are derived from NASA's MERRA-2 reanalysis dataset. More information on MERRA-2 can be found here. More information on ERA5 data sets can be found here.

All datasets are updated monthly ( and deliver global horizontal (GHI), direct normal (DNI), and diffuse (DIF) irradiance. As well as the weather data available as described in “Which weather data should I pick”, a user can select either the standard or extended solar data variable list. The standard variable set is global horizontal irradiance, direct normal irradiance, and diffuse horizontal irradiance. Extended includes these and adds clear-sky GHI, cloud index, Linke turbidity factor, solar zenith and azimuth angles.