If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Lisbon: The hottest months are usually July and August with an average temp of 63°F, while the coldest months are January and February with an average of 22°F. The snowiest months in Lisbon are January, March, February, and April, with each month seeing an average of 12 inches of snowfall.