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.
Average temperatures comfortably sit in the mid-60s to high 80s year-round, but rain showers are less prevalent from mid-June to August (Oahu's summer season), so tourists flock to the island to take advantage of the sunnier weather.