If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Beaver Island: The hottest months are usually July and August, with an average temperature of 17°C, while the coldest months are February and January, with an average of -5°C. The snowiest months in Beaver Island are January, November, February and March, with each month seeing an average of 30 cm of snowfall.