The paper presents the statistical analysis’ results of major models of the solar radiation intensity onto an inclined plane. Models with various degrees of complexity: from the simplest classical isotropic model to the most complex anisotropic model (the Perez model) were analyzed. The data yielded by the theoretical models were compared with a four-year measurement database from the actinometric station in the SolarLAB Photovoltaic Laboratory in Wrocław. Also the potential benefits of using albedo data characteristic of the measurement location versus the classical 0.2 albedo assumption were examined.