August in Kerrville is the hottest month of the year. In August, the weather in Kerrville is typically hot. Average daily high temperature in August is about 32 degrees above zero. On average, Kerrville has 16 sunny, 10 partly cloudy, 4 rainy, and 1 cloudy day in August. The rains are usually light. August as well as January, May, September, and December is considered the most uncomfortable time to visit Kerrville.