If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Galena: The hottest months are usually July and August with an average temp of 69°F, while the coldest months are January and February with an average of 26°F. The snowiest months in Galena are January, December, March, and November, with each month seeing an average of 10 inches of snowfall.