JLMandPaul - My husband and I were on St. John at the end of March (we had perfect weather - it hadn't rained in a month at that point, so you must have gotten the drought-breaking storm!) and I used self-tanner before I went - my doc said it was fine. I used a Neutrogena brand bronzer/self-tanner and it looked pretty good.
DazedandConfused - what do you mean it's not warm on St. John in April?? It's a tropical island! We had 85-90 deg. weather every day. That's why people go there in the winter, cause it's so nice and HOT when it's cold everywhere else! Maybe you meant another St. John - I'm talking about the US Virgin Island...of course, here in Vermont, it's not what I'd call warm.