If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Grand Anse: The hottest months are usually April and May with an average temp of 83°F, while the coldest months are July and August with an average of 80°F. The rainiest months in Grand Anse are January, December, May, and November, with each month seeing an average of 10 inches of rainfall.