If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Amherst: The hottest months are usually July and August with an average temp of 67°F, while the coldest months are January and February with an average of 23°F. The snowiest months in Amherst are March, January, December, and April, with each month seeing an average of 7 inches of snowfall.