My guess would be 11

probably more important than the temperature is the 6 months of rain and 6 months of dry season. this is what most affects plants down here. chris

Zone ratings stop at Zone 11, which is any climate where the normal annual lowest temperature is at 40F or above. This includes the Florida Keys, Tampico area of Mexico southward, all of the Caribbean, all of coastal Hawaii
(Zone 10 in the mountains of Hawaii), etc. There are no Zone 11 regions on the mainland part of the U.S. The only Zone 10 areas on the mainland are southern coastal California (10A/B), the lower part of the Rio Grande Valley, mainly the eastern two thirds of Cameron County (10A with South Padre Island borderline 10B), and coastal central Florida (10A) and all of South Florida 10A/B), with the Keys being Zone 11.

John

P.S. the Caribbean would be theoretically Zones 12 and 13 for the coastal areas, since these area don't get below 50F and 60F, respectively. I believe the all-time record low for the Virgin Islands is 62F, whereas it is 41F for Key West, FL, and 27F for Miami, just to give you some perspective on just how TROPICAL the Caribbean really is!
John

Hi
Any land mass within the tropics would have generally the same temps year around but highly modified by altitude. The higher the mountain the cooler the temps, "Summer is usually when it rains the most Winter when it rains the least. Generally you can subtract about 10 degrees of temp. for every 1500 feet of altitude . So as a general guideline you can subtract 10 degrees from 70. Above 12,000
the air can no longer hold heat so it's permanently cold while sealevel to around 2000 feet are in the eighties.
Seasons of temp variation only happen above and below the tropical latitudes..
So the really question about VI should be any mountains above 1500 feet?? If so there are at least two climate zones if not it will generally be in the low eighties.
So actually there are far more climate zones within the tropics than in the seasonal zones but dictated by average temps not seasonal.
In North America Californis is an outstanding example, Zonal designations are useless there due to the montains.
gary

"...I believe the all-time record low for the Virgin Islands is 62F..."

To where I will now be moving.