Weather will likely play an important role when you plan your trip to Parry Sound, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually July and August with an average temp of 63°F, while the coldest months are January and February with an average of 23°F. The snowiest months in Parry Sound are January, February, March, and December, with each month seeing an average of 21 inches of snowfall.