December in Sinsk is the most freezing month of the year. In December, the weather in Sinsk is typically freezing. Average daily high temperature in December is about 28 degrees below zero. On average, Sinsk has 27 cloudy, 2 sunny, 1 snowy, and 1 partly cloudy day in December. The snowfalls are usually light. December as well as January, February, March, and May is considered the most uncomfortable time to visit Sinsk.