The knowledge of the probability density function of wind speed is key information for determining wind energy potential of the specified region. In literature, the Weibull distribution is widely-used and accepted distribution to express the probability density function of wind speed data. However, the Weibull distribution does not exhibit good fitting for all wind speed data measured at different geographical locations throughout the world. Thus, in this study, it is proposed that a better fitting of wind speed data and a better estimating wind power density is possible with new modified Weibull distribution (MWD). Also, we compare the performance of the MWD relative to the Weibull distribution by using wind speed data measured in the different regions of Turkey. The results point out that the MWD shows good fitting for most of the considered wind speed data cases. Thus, the MWD can be alternative for assessment of wind energy potential.