May in Jan Mayen is the sunniest month of the year. In May, the weather in Jan Mayen is typically cold. Average daily high temperature in May is about 2 degrees above zero. On average, Jan Mayen has 21 cloudy, 7 rainy, 2 sunny, and 1 snowy day in May. The rains are usually light. May as well as January, August, September, and October is considered the most uncomfortable time to visit Jan Mayen.