If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Maryville: The hottest months are usually July and August with an average temp of 73°F, while the coldest months are January and February with an average of 32°F. The snowiest months in Maryville are January, November, February, and December, with each month seeing an average of 5 inches of snowfall.