The most pleasant months of the year for Osage are June, September and August. In Osage, there are 2 comfortable months with high temperatures in the range of 70-85°. July is the hottest month for Osage with an average high temperature of 87.5°, which ranks it as warmer than most places in Wyoming. December is the snowiest month in Osage with 7.3 inches of snow, and 8 months of the year have significant snowfall. There are few days during the summer when the humidity becomes unpleasant.