Gosh, sorry to hear about the poor weather. That's such a bummer. Glad to hear you still enjoyed the trip.
Weather/climate was the first thing I checked when we were planning our trip. I know Caribbean have very distinct rainy (and hurricane) season. From what I gathered, the rain starts around May thru Oct., and hurricane from June thru Oct. We were quite lucky in our first Magic(al) cruise. We had 4 days of cloudless skies, even though it was in the middle of the rain & hurricane season. We didn't know any better then. We just booked and went.
Our 2nd trip was picked during their dry season. However, the water temperature in Jan/Feb was a bit cold for our kids. So, this time around, we tried to pick a date just before the rainy season. Unfortunately, Easter is late next year, so for a Western cruise, we had to settle for 5/10/03. Hopefully, we'll just miss the rain...