August in South Dayton is the sunniest month of the year. In August, the weather in South Dayton is typically warm. Average daily high temperature in August is about 23 degrees above zero. On average, South Dayton has 18 sunny, 9 rainy, and 4 partly cloudy days in August. The rains are usually moderate. August as well as July is considered the most comfortable time to visit South Dayton.