In this study, by using long-term measuring data for the Mediterranean Region, total solar radiation intensity, which appears on a horizontal surface, has been calculated by utilizing from equations that are developed from certain patterns presented in the literature and results have been compared. Statistical parameters of these values, which are derived from these functions, have been calculated according to measured values. Although measured solar radiation values show fluctuations within and by years, it is observed that developed equations represent long-term measuring values in the best possible way. Values that arise as a result of modeling are compared with values given for the Mediterranean Region in the literature. It is perceived that those improved patterns can be used for estimating average monthly total solar radiation that appear on horizontal surfaces in provinces involved in the Mediterranean Region.