We have been the last 2 years around Christmas. Once arriving a week before and staying after Christmas for a few days. Once arriving a week before and leaving the 22nd. Both were good trips, but the one staying after Christmas was not good after the 25th. We learned our lesson. Your dates should be great. The crowds will decend on the 25th. As for weather, you just never know. Last year I wore shorts some days, jeans some days, and a winter coat one night with thin gloves to keep my hands warm. Pack for everything. We did swim a few days, but it was overcast quite a few days too. The water is warm in the pools--heated, but the getting out of the pool part was not fun when it was chilly.