Weather will likely play an important role when you plan your trip to St. Petersburg, 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 24°F. The snowiest months in St. Petersburg are January, December, November, and February, with each month seeing an average of 13 inches of snowfall.