In December, the weather in Kopeysk is typically freezing. Average daily high temperature in December is about 10 degrees below zero. On average, Kopeysk has 22 cloudy, 4 sunny, 3 snowy, and 2 partly cloudy days in December. The snowfalls are usually light. December as well as January, February, April, and October is considered the most uncomfortable time to visit Kopeysk.