December in Hillerød is the rainiest and the windiest month of the year. In December, the weather in Hillerød is typically cold. Average daily high temperature in December is about 4 degrees above zero. On average, Hillerød has 24 rainy, 5 cloudy, and 2 sunny days in December. The rains are usually moderate. December as well as January, February, October, and November is considered the most uncomfortable time to visit Hillerød.