Though weather is just one factor, it can really affect your travel plans, especially when you're planning an extended stay in Amherst. The hottest months are usually July and August with an average temp of 68°F, while the coldest months are January and February with an average of 19°F. The snowiest months in Amherst are April, March, December, and January, with each month seeing an average of 7 inches of snowfall.