February in Grande-Synthe is the coldest month of the year. In February, the weather in Grande-Synthe is typically cold. Average daily high temperature in February is about 6 degrees above zero. On average, Grande-Synthe has 13 rainy, 8 cloudy, 5 sunny, and 3 partly cloudy days in February. The rains are usually moderate. February as well as January, October, November, and December is considered the most uncomfortable time to visit Grande-Synthe.