Generally, the Caribbean is safe to travel to at all times. Typically, you will pay more and find more crowds when you travel from December to April. If you don't mind the crowds, you will typically find the best weather (meaning less rain) during these months. If you are looking for less 	crowds and better discounts, travel from April to December might be within your best interest. During these months, the weather might not be perfect, but perfectly fine as it is the rainy/hurricane season from June to November.