If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Portobelo: The hottest months are usually May and September with an average temp of 80°F, while the coldest months are January and February with an average of 79°F. The rainiest months in Portobelo are November, July, August, and October, with each month seeing an average of 14 inches of rainfall.