Planning for the weather is a good way to make your trip to St. Petersburg relaxing and enjoyable, especially when you’re splurging. The hottest months are usually July and August, with an average temperature of 16°C, while the coldest months are January and February, with an average of -4°C. The snowiest months in St. Petersburg are January, December, November and February, with each month seeing an average of 33 cm of snowfall.