The most pleasant months of the year for the 91980 zip code are October, May and June. In the 91980 zip code, there are 5 comfortable months with high temperatures in the range of 70-85°. August is the hottest month for the 91980 zip code with an average high temperature of 90.9°, which ranks it as about average compared to other places in California. December is the snowiest month in the 91980 zip code with 0.0 inches of snow, and no months of the year have significant snowfall. There are few days during the summer when the humidity becomes unpleasant.