January in Chatham is the coldest month of the year. In January, the weather in Chatham is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, Chatham has 10 rainy, 10 sunny, 7 partly cloudy, and 4 cloudy days in January. The rains are usually moderate. January as well as February, March, and December is considered the most uncomfortable time to visit Chatham.