January in Block Island is the snowiest and the coldest month of the year. In January, the weather in Block Island is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, Block Island has 10 sunny, 10 partly cloudy, 7 rainy, 3 cloudy, and 1 snowy day in January. The rains are usually moderate. January as well as February, March, and December is considered the most uncomfortable time to visit Block Island.