January in Koblenz is the coldest month of the year. In January, the weather in Koblenz is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, Koblenz has 13 rainy, 13 cloudy, 3 sunny, and 2 partly cloudy days in January. The rains are usually light. January as well as February, November, and December is considered the most uncomfortable time to visit Koblenz.