We were at CSA the first week of Dec last year. The days were very, very hot and the nights were warm. The winds always die down in the evening, which makes it feel even warmer. It's a beautiful time of year to be in Jamaica!
Expect highs in the mid 80's and lows in the mid 70's. As far as rian or as the Jamaican's call liquid sunshine,you are at the tail end of the rainy season (11/30) so anything can happen.
A rainy day at at Couples on vacation is much better then a sunny day at home at work