We were there last year from the 14th of Dec. through the holidays, as I've done years in the past. I'm a "take your kids out of school mom" to avoid the large crowds. You see the crowds pick up a little each day. If I remember correctly, seems like it was mild until around the 20th. You should be fine. The last few days may be more hectic, but the masses of people usually are noticable around the 23rd on. We will be there this year the same time 15-22, for that reason. Enjoy! In my opinion, it's the best time to go.