The solar hourly irradiation received at ground level estimated by the databases HelioClim-3v4, HelioClim-3v5 and Copernicus Atmosphere Monitoring Service (CAMS) Radiation Service are compared to measurements made in stations in Oman and Abu Dhabi. The correlation coefficients are greater than 0.97. The relative bias is less than 5%. Each database captures accurately the temporal and spatial variability of the irradiance field. The three databases are reliable sources to assess solar radiation.