January in Grantville is the snowiest and the coldest month of the year. In January, the weather in Grantville is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, Grantville has 13 partly cloudy, 7 sunny, 4 rainy, 4 cloudy, and 3 snowy days in January. The rains are usually heavy. January as well as February, March, November, and December is considered the most uncomfortable time to visit Grantville.