The Weibull density function has been used to estimate the wind energy potential in Grenada, West Indies. Based on historic recordings of mean hourly wind velocity this analysis shows the importance to incorporate the variation in wind energy potential during diurnal cycles. Wind energy assessments that are based on Weibull distribution using average daily/seasonal wind speeds fail to acknowledge that wind speed probabilities can vary significantly during day and night. In particular where wind energy estimation is linked to electricity loads neglecting diurnal wind patterns can result in significant under/overestimation of wind power potential. (C) 2003 Elsevier Science Ltd. All rights reserved.