Cooling tower performance calculations are usually performed numerically. In this paper, a simple differential equation for counter flow wet cooling tower is solved analytically taking into consideration the non-linear dependency of the saturated air enthalpy on temperature. The method allows analytical calculation of cooling tower performance with large cooling ranges. The analytically obtained values are compared with the well-known logarithmic mean enthalpy method (LMED) and corrected LMED method. It is seen that analytically obtained values are much more accurate than the values obtained using these two methods. The analytical results are also compared with experimental ones and it is seen that there is a good agreement between them.