Summer: June to August is summer season with the highest temperature being 70 degrees Fahrenheit.
Fall: September to November is fall season with good amount of rainfall. The temperature is pleasant.
Winters: December to February is winter which peaks after Christmas and reach below freezing temperatures.
Spring: March to May welcomes spring season and event though has low temperatures, makes up for a good time to see the city.
The best time to visit Mont St. Michel is during spring and summer season eventhough tourists visit the place in fall season to witness the new bridge completely go under water (a rare but curious phenomenon).