In December, the weather in Frankfurt am Main is typically cold. Average daily high temperature in December is about 4 degrees above zero. On average, Frankfurt am Main has 11 cloudy, 9 rainy, 7 partly cloudy, 3 sunny, and 1 snowy day in December. The rains are usually moderate. December as well as January, February, March, and April is considered the most uncomfortable time to visit Frankfurt am Main.