There's nothing like an all-inclusive holiday in Arcahaie to rejuvenate you, especially when you know what to expect from the elements. Here's some information to help you decide when to book: The hottest months are usually July and August, with an average temperature of 27°C, while the coldest months are January and December, with an average of 24°C. January and December are the driest months, while October and August are the rainiest months.