August in Newnan is the cloudiest month of the year. In August, the weather in Newnan is typically hot. Average daily high temperature in August is about 29 degrees above zero. On average, Newnan has 14 rainy, 9 sunny, and 8 partly cloudy days in August. The rains are usually heavy. August as well as January, February, June, and July is considered the most uncomfortable time to visit Newnan.