You'll likely spend much of your trip indoors, but if you want to see more of the area, taking a look at local weather data can help you. 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.