January in St. Louis is the windiest and the coldest month of the year. In January, the weather in St. Louis is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, St. Louis has 11 partly cloudy, 9 sunny, 8 cloudy, and 3 rainy days in January. The rains are usually light. January as well as February, March, and December is considered the most uncomfortable time to visit St. Louis.