0.96). The accuracy of Businger and Van bavel methods in all regions were low with RMSE and MAE values greater than 0.9 and 0.55 mm per day, respectively. In arid, humid and semi-humid regions of Iran, Penman 1948 and Penman Wright 1972 methods with RMSE and MAE values less than 0.39 mm per day and in semi- arid regions of Iran Penman Wright 1972 methods and Penman 1948 with RMSE and MAE values less than 0.35 mm per day had the highest accuracy.]]>