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