The most pleasant months of the year for the 78021 zip code are March, November and April. In the 78021 zip code, there are 4 comfortable months with high temperatures in the range of 70-85°. August is the hottest month for the 78021 zip code with an average high temperature of 98.0°, which ranks it as one of the hottest places in Texas. December is the snowiest month in the 78021 zip code with 0.2 inches of snow, and no months of the year have significant snowfall. The most uncomfortably humid months are July, June and August.