This paper is based on findings resulting from ASHRAE Research Project RP-1561.

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, a long-term climate model evaluation was performed by running WRF over 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).