If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Oviedo: The hottest months are usually July and August with an average temp of 81°F, while the coldest months are January and February with an average of 64°F. The rainiest months in Oviedo are August, September, July, and June, with each month seeing an average of 8 inches of rainfall.