January in Watertown is the cloudiest and the most freezing month of the year. In January, the weather in Watertown is typically freezing. Average daily high temperature in January is about 7 degrees below zero. On average, Watertown has 21 cloudy, 4 partly cloudy, 3 snowy, and 3 sunny days in January. The snowfalls are usually light. January as well as March, April, and November is considered the most uncomfortable time to visit Watertown.