Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity, defined as the 50 yr wind speed (10 min averages) under standard conditions, i.e., 10 m over a homogeneous terrain with the roughness length 0.05 m. The sites are Skjern (15 yr), Kegnaes (7 yr), Sprog( (20 yr), and Tystofte (16 yr). The measured data are wind speed, wind direction, temperature and pressure. The wind records are cleaned for terrain effects by means of WA S P (Mortensew et al., Technical Report I-666 (EN), Ris( National Laboratory, 1993. Vol. 2: User's Guide): assuming geostrophic balance, all the windvelocity data are transformed to friction velocity u ร and direction at standard conditions by means of the geostrophic drag law for neutral stratification. The basic wind velocity in 308 sectors are obtained through ranking of the largest values of the friction velocity pressure ru 2 ร =2 taken once every two months. The main conclusion is that the basic wind velocity is significantly larger at the west coast of Jutland รฐ25 AE 1 m=sร than at any of the other sites รฐ22 AE 1 m=sร. These results are in agreement with those obtained by Jensen and Franck