Hi there, Rita!
Mid-December weather in Florida is just beautiful. Historically, high temperatures are in the low-mid 70s, with ow temperatures in the mid-50s (all temperatures Fahrenheit). It's not a particularly rainy month, either, so you'll enjoy mostly sunny days and brisk evenings.
From Thanksgiving through early December, crowds see a sharp decrease, But around two weeks prior to Christmas, the crowd levels start to increase, coinciding with school vacations and family trips. Christmas week is one of the most crowded periods at Walt Disney World -- lots of holiday cheer to be found among its Guests.
Christmas decorations start going up at the Walt Disney World Resort in early November, and are in full swing by Thanksgiving. By the time of your visit, the holiday magic will be permeating the entire World!
You'll find a variety of special holiday activities throughout the Parks and at the Resort hotels. Make sure to pick up a Times Guide at each Park, and grab a recreation sheet when you check in to your hotel. If you;d like to check in with a specific Park or a particular activity you're looking for, I'd be glad to help you with a more tailored response.
One must-do special event is
Mickey's Very Merry Christmas Party. It's a delightful celebration of winter fun in the Magic Kingdom, featuring special fireworks and parades. A special ticket is required for admission.
Have a wonderful time!
See you later, celebrator,
-Deborah B.