Weather is probably a major factor when you plan your trip to Castlegar, 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 62°F, while the coldest months are December and January with an average of 25°F. The snowiest months in Castlegar are January, December, October, and February, with each month seeing an average of 11 inches of snowfall.