In this thesis are proposed methodologies to estimate gust factors at the extreme wind speed for Calgary from measurements at lower wind speeds using the Generalized Extreme Value (GEV) distribution. The GEV distribution is fitted to the data in order to select the most probable high value of gust factor. In the first part of this thesis variations of the GEV parameters to hourly mean wind speeds are investigated. The second part of this thesis addresses the methods for estimation of gust factors. Results show that GEV parameters are constant at extreme wind speeds and gust factors decrease with increasing wind speeds. Representative values of gust factors were found for extreme wind speeds. These values were found to be significantly lower than the gust effect factor for static structures mandated in the National Building Code of Canada (NBC) and the gust factor used in IEC Standard 61400-2 for wind turbines.