If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Garapan: The hottest months are usually July and August, with an average temperature of 28°C, while the coldest months are February and March, with an average of 27°C. The rainiest months in Garapan are August, October, September and July, with each month seeing an average of 385 mm of rainfall.