A method is described for determining wind speed frequency distributions at any height up to ∼200 m above ground for a meteorological station where wind speed and direction is measured at a low reference level (usually 10 m) and which reports routine meteorological data at least once every 3 h. The roughness characteristics of the terrain surrounding the station must be known in detail, because the model calculates the rate of growth of internal boundary layers resulting from discontinuities in roughness as well as the shape of the wind profile in the various layers. The rate of growth of the internal boundary layers has been determined from work by Pasquill (1972). The shape characteristics of the profile are determined as a function of roughness length and of stability by the aid of measurements from three Swedish 100 m masts. The method is successfully tested against an independent set of data from a 100 m mast. Also given are some results from application of the method to Swedish data. The method has been developed for comparatively flat rural terrain and is not valid for urban conditions and mountainous areas.