December in Atlanta is the cloudiest month of the year. In December, the weather in Atlanta is typically warm. Average daily high temperature in December is about 11 degrees above zero. On average, Atlanta has 11 rainy, 9 sunny, 7 partly cloudy, and 4 cloudy days in December. The rains are usually heavy. December as well as January, February, March, and July is considered the most uncomfortable time to visit Atlanta.