If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Birchwood: The hottest months are usually July and August with an average temp of 66°F, while the coldest months are January and February with an average of 19°F. The snowiest months in Birchwood are March, April, January, and February, with each month seeing an average of 9 inches of snowfall.