In December, the weather in Diekirch is typically cold. Average daily high temperature in December is about 3 degrees above zero. On average, Diekirch has 10 rainy, 10 cloudy, 6 partly cloudy, 4 sunny, and 1 snowy day in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Diekirch.