Mid-march is also nice - temps will likely be in the mid 60s-low 70s. The ocean will still be too cool for my tastes - but in the upper 60's. Resort activities are ramped up at this time too. Most of the activities run year-round - but some are more enjoyable when the air temps are more comfy than in Jan -early Feb.
Even with (and to some extent - due to) to lower point costs, the resort is still pretty busy with a lot of families. December, January and early February are slower than most other times of the year. The fall will still have good occupancy, but with fewer school aged children.
Enjoy!