Weather is probably a major factor when you plan your trip to Petrozavodsk, 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 58°F, while the coldest months are January and February with an average of 20°F. The snowiest months in Petrozavodsk are January, February, March, and December, with each month seeing an average of 87 inches of snowfall.