Surface air temperature estimates have been calculated from satellite-derived surface skin temperature measurements within the EUSTACE project. Research was done to investigate the relationship between these air and skin temperatures based on temporally and spatially collocated observations, and empirical relationships have been derived. These have then been applied to the satellite skin temperatures used in the EUSTACE project to estimate surface air temperatures. The relationships have been derived separately for the land, ice and ocean regions, and are described further in the EUSTACE Scientific and Product User Guides.