December in Sonderborg is the windiest month of the year. In December, the weather in Sonderborg is typically cold. Average daily high temperature in December is about 4 degrees above zero. On average, Sonderborg has 19 rainy, 8 cloudy, 3 sunny, and 1 partly cloudy day in December. The rains are usually moderate. December as well as January, February, March, and October is considered the most uncomfortable time to visit Sonderborg.