The most pleasant months of the year for San Mateo are May, September and October. In San Mateo, there are 3 comfortable months with high temperatures in the range of 70-85°. July is the hottest month for San Mateo with an average high temperature of 89.7°, which ranks it as about average compared to other places in New Mexico. December is the snowiest month in San Mateo with 4.5 inches of snow, and 5 months of the year have significant snowfall. Days with noticeable humidity are rare throughout the year.