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 temperature of 15°C, while the coldest months are January and February, with an average of -15°C. The snowiest months in Irkutsk are April, January, December and February, with each month seeing an average of 31 cm of snowfall.