If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Willits: The hottest months are usually July and August with an average temp of 66°F, while the coldest months are February and December with an average of 45°F. The rainiest months in Willits are December, January, March, and February, with each month seeing an average of 8 inches of rainfall.