January in Newnan is the windiest and the coldest month of the year. In January, the weather in Newnan is typically warm. Average daily high temperature in January is about 10 degrees above zero. On average, Newnan has 14 sunny, 11 partly cloudy, and 6 rainy days in January. The rains are usually moderate. January as well as February, June, July, and August is considered the most uncomfortable time to visit Newnan.