It's weird in December is WDW. We were there last year the first full week in Dec, and there were some cold nights. Lows around 40, maybe in the upper 30's. I just put on a fleece jacket and some light stretchy fleece gloves I had-and I was glad I had gloves! However, we were there in Dec 2001 and It was warm ~80 for highs all week and fairly humid. Brought pants and never wore them! Understand, the averages are highs in the low 70's and lows in the low 50's. Lovely weather by my northen standards, but many would still want a jacket at night. Go to the weather channel page for Orlando and check out the averages, especially the records for the times your going. The averages are wonderful, the but the potential range of temps goes from very hot to burrrrrr. Watch the long term forecasts before you go, and pack layers. The low was 40 the first night there last year, but it beats the heck out of the foot of snow we left that morning. I'll deal for that trade.