If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Oakley: The hottest months are usually July and August with an average temp of 76°F, while the coldest months are January and February with an average of 35°F. The snowiest months in Oakley are January, December, March, and November, with each month seeing an average of 6 inches of snowfall.