The purpose of this paper is to establish a basis for determining the accuracy level required in load prediction models by comparing fatigue results of a composite material wind turbine blade for a set of experimental wind loads. Wind data for two successive years is considered separately as two load cases to calculate aerodynamic loads. These loads are used in monthly and yearly cycles to perform fatigue analysis and the difference in safety life and damage for successive years is calculated, to check, if faithful prediction of hourly or daily wind speeds for a wind forecast model is required. Thus, the dynamics of wind forecasting can be improved for safe, reliable and economical operation of the wind turbines. This report details blade modeling procedure, calculation of aerodynamic loads from the collected wind data and fatigue analysis of the wind turbine blade.