December in Aachen is the rainiest and the windiest 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 21 rainy, 5 cloudy, 4 sunny, and 1 partly cloudy 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.