January in Jacksonville is the snowiest and the coldest month of the year. In January, the weather in Jacksonville is typically freezing. Average daily high temperature in January is about zero. On average, Jacksonville has 14 cloudy, 7 sunny, 5 snowy, 3 partly cloudy, and 2 rainy days in January. The snowfalls are usually light. January as well as February, March, and December is considered the most uncomfortable time to visit Jacksonville.