The best time to visit the Caribbean is during November and March. The hurricane season falls loosely between August and early November. Earlier than this, from April to August, it is intensely hot and humid with temperatures reaching the early 40s Celsius. While it is possible to visit the islands during this time, the most pleasant season to visit the Caribbean is November to March, when temperatures are cooler and there is less chance of rain.
It can rain in the Caribbean at any time of year, so its best to be prepared for all weathers - but usually downpours are brief, and a welcome hit of cool in the heat.