August in La Crosse is the sunniest month of the year. In August, the weather in La Crosse is typically warm. Average daily high temperature in August is about 25 degrees above zero. On average, La Crosse has 22 sunny, 7 partly cloudy, and 2 rainy days in August. The rains are usually light. August as well as September is considered the most comfortable time to visit La Crosse.