Hi Teresa,
The weather in December can be a bit unpredictable. While we often run our air-conditioning on Christmas, it can also be cold (or at least what we consider cold in Central Florida). Generally, during December and January, the highs run in the low 70s with lows in the low to mid 50s. This year, however, temps have been running higher than normal and are predicted to remain about 10 degrees warmer than usual through Christmas.
Even so, when the sun goes down, you may find it cool. Layering is the key. I'd recommend short sleeves with shorts or jeans during the day and a light jacket or wind breaker at night. If you are cold-natured, you might even want a sweatshirt after dark.
You will be happy to know that all the swimming pools at
Walt Disney World are heated year-round to about 82 degrees, so even if it suddenly turns cooler, you and your family can still enjoy the resort pools.
Thanks for dropping in at the Disney Parks Moms Panel, Teresa. Enjoy your holiday visit!
Wilma