December in Aachen is the snowiest month of the year. In December, the weather in Aachen is typically cold. Average daily high temperature in December is about 5 degrees above zero. On average, Aachen has 12 rainy, 8 cloudy, 7 partly cloudy, 3 sunny, and 1 snowy day in December. The rains are usually moderate. December as well as January, February, March, and November is considered the most uncomfortable time to visit Aachen.