February in Groton is the windiest month of the year. In February, the weather in Groton is typically cold. Average daily high temperature in February is about 2 degrees above zero. On average, Groton has 9 sunny, 8 rainy, 8 partly cloudy, 3 cloudy, and 1 snowy day in February. The rains are usually heavy. February as well as January, March, and December is considered the most uncomfortable time to visit Groton.