December in Udachny is the most freezing month of the year. In December, the weather in Udachny is typically freezing. Average daily high temperature in December is about 28 degrees below zero. On average, Udachny has 19 cloudy, 6 sunny, and 6 partly cloudy days in December. December as well as January, February, March, and May is considered the most uncomfortable time to visit Udachny.