There's nothing like an all-inclusive holiday in Sosúa to revive you, especially when you know what kind of weather to expect. Here's some information to help you decide when to book: The hottest months are usually August and September, with an average temperature of 27°C, while the coldest months are March and February, with an average of 24°C. July and June are the driest months, while November and October are the rainiest months.