If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Mena: The hottest months are usually July and August with an average temp of 77°F, while the coldest months are January and February with an average of 44°F. The rainiest months in Mena are May, April, March, and December, with each month seeing an average of 7 inches of rainfall.