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 Mandeville: The hottest months are usually August and September, with an average temperature of 25°C, while the coldest months are February and January, with an average of 22°C. The rainiest months in Mandeville are September, October, May and August, with each month seeing an average of 248 mm of rainfall.