If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Puerto San Jose: The hottest months are usually April and March with an average temp of 82°F, while the coldest months are January and December with an average of 80°F. The rainiest months in Puerto San Jose are June, September, October, and August, with each month seeing an average of 11 inches of rainfall.