Planning for the weather is a good way to make your trip to Irkutsk relaxing and enjoyable, especially when you're splurging. The hottest months are usually July and June with an average temp of 60°F, while the coldest months are January and February with an average of 6°F. The snowiest months in Irkutsk are April, January, December, and February, with each month seeing an average of 12 inches of snowfall.