In December, the weather in Velenje is typically cold. Average daily high temperature in December is about 2 degrees above zero. On average, Velenje has 11 cloudy, 7 rainy, 7 partly cloudy, 5 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 Velenje.