January in Frankfurt am Main is the coldest month of the year. In January, the weather in Frankfurt am Main is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, Frankfurt am Main has 15 rainy, 12 cloudy, and 4 sunny days in January. The rains are usually light. January as well as February, November, and December is considered the most uncomfortable time to visit Frankfurt am Main.