January in Saint-Nazaire is the rainiest and the coldest month of the year. In January, the weather in Saint-Nazaire is typically cold. Average daily high temperature in January is about 9 degrees above zero. On average, Saint-Nazaire has 15 rainy, 6 sunny, 6 cloudy, and 4 partly cloudy days in January. The rains are usually heavy. January as well as February, November, and December is considered the most uncomfortable time to visit Saint-Nazaire.