This study provides an insight into the spatial distribution of uncertainty of Direct Normal Irradiation (DNI)as estimated from the relative cross-comparison of five data sources offering solar resource and climate data for Europe: Meteonorm, Satel-Light, NASA SSE, SOLEMI, and PVGIS. The results show that within 90% of the study area the uncertainty of DNI expressed by relative standard deviation may go up to 17%. This high value indicates a need for further improvement of the data inputs and solar radiation models.