The most pleasant months of the year for Jefferson are May, October and September. In Jefferson, there are 3 comfortable months with high temperatures in the range of 70-85°. July is the hottest month for Jefferson with an average high temperature of 94.6°, which ranks it as warmer than most places in Oklahoma. December is the snowiest month in Jefferson with 3.5 inches of snow, and 5 months of the year have significant snowfall. July is the most humid month, though humidity is low for most of the year.