Planning for the weather is an important factor for making your trip to Cape Sable Island a success, especially when you're splurging. The hottest months are usually July and August with an average temp of 59°F, while the coldest months are February and January with an average of 29°F. The snowiest months in Cape Sable Island are February, December, January, and March, with each month seeing an average of 13 inches of snowfall.