This paper presents the results of ASHRAE Research Project RP-1561@ Procedures to Adjust Observed Climatic Data for Regional or Mesoscale Variations. This project included a Weather Research Forecast (WRF) modeling campaign designed to cover ten significant climate regions across North America. Model results were compared against mesoscale monitoring data to assess the model??s performance for a single year??s hourly weather. Subsequently@along-term climatemodel evaluation was performed by runningWRFover four regions in North America for eight years. Overall@ the model performed well against observed temperature and humidity@ reasonably well against observed wind@ and relatively poorly against observed solar radiation and precipitation. Guided by this evaluation@ a complete mesoscale numerical modeling procedure was developed for coastal regions@ mountain valleys@ mountain plateaus@ and major city centers to provide site-specific climate data (i.e.@ a freely available software solution for developing localized climate data).