Surface incoming solar (SIS) radiation, also referred to as shortwave global irradiance, is an essential climate variable and highly relevant for applications in the fields of climate monitoring, solar energy or agriculture. SIS can be retrieved from geostationary satellite sensors with a continuous spatial and temporal coverage and thus complements station-based estimates. This report documents the “HelioMont” methodology which was developed at MeteoSwiss within the EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) project to calculate SIS including its components from Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) data.