The Caribbean has a climate of perpetual spring and summer with temperatures ranging from the upper 70s in the winter to the lower 80s in the summer. Sharing many of the same characteristics but not technically part of the Caribbean, winter temperatures in the Bahamas and Bermuda hover closer to 70.
Rainy seasons vary by island, but usually late spring (May and June) and fall (October and November) are the wettest months. At this latitude, however, the showers are brief and heavy, and the sun is often out again before you can pack up and leave the beach.
Hurricane season in the Caribbean stretches from June through November. As summer progresses, the hurricane probability increases, and the most likely month for a storm is September. However, the Dutch Leeward Islands--Aruba, Bonaire, and Curacao-- and Trinidad and Tobago are south of the hurricane zone and are the safest bets during peak storm season.