The word caste is actually a corrupted Portuguese word. The more useful term for sociological groupings is Jati.. Jati as used in South Asia is a very close fit to the definition of people group..
Water temperatures in the Virgin Islands do not change greatly from summer to winter, however the 4 or 5 degree change is noticeable to those acclimated to consistently warm tropical weather. In the summer months the water temperature is about 83 degrees and in the winter about 79 degrees.
The best time to visit the U.S. Virgin Islands is April to June, when you can expect mild weather and very little rainfall. In the USVI's peak season, from December to March, the temperature ranges from the mid-70s to high 80s with breezy evenings.