January in Greater Sudbury is the most freezing month of the year. In January, the weather in Greater Sudbury is typically freezing. Average daily high temperature in January is about 8 degrees below zero. On average, Greater Sudbury has 18 snowy, 11 cloudy, and 2 sunny days in January. The snowfalls are usually moderate. January as well as February, April, October, and November is considered the most uncomfortable time to visit Greater Sudbury.