Weather will likely play an important role when you plan your trip to Petergof, 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 60°F, while the coldest months are January and February with an average of 25°F. The snowiest months in Petergof are February, January, December, and November, with each month seeing an average of 52 inches of snowfall.