January in Rennes is the coldest month of the year. In January, the weather in Rennes is typically cold. Average daily high temperature in January is about 8 degrees above zero. On average, Rennes has 12 rainy, 8 cloudy, 7 partly cloudy, and 4 sunny days in January. The rains are usually moderate. January as well as February, March, October, and November is considered the most uncomfortable time to visit Rennes.