I personally wouldn't chance it in December. On allears.net they have been talking about how the shows have been canceled due to the cold weather. Just remember that the show is outdoors so if there is any chill in the air, you will be sitting in it, or if it gets below a certain degree, Disney will just cancel it. If I were you, I would look into the HDDR over at FW, at least you will be in a warm building. Have a great trip.