If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Stevensville: The hottest months are usually July and August with an average temp of 63°F, while the coldest months are December and January with an average of 24°F. The snowiest months in Stevensville are January, December, February, and April, with each month seeing an average of 6 inches of snowfall.