January weather forecast in Herndon

January in Herndon is the snowiest and the coldest month of the year. In January, the weather in Herndon is typically cold. Average daily high temperature in January is about 6 degrees above zero. On average, Herndon has 9 sunny, 9 partly cloudy, 6 rainy, 6 cloudy, and 1 snowy day in January. The rains are usually heavy. January as well as February, March, July, and August is considered the most uncomfortable time to visit Herndon.