Weather is probably a major factor when you plan your trip to Campobello Island, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and July with an average temp of 61°F, while the coldest months are January and February with an average of 29°F. The snowiest months in Campobello Island are January, February, December, and March, with each month seeing an average of 15 inches of snowfall.