After Thanksgiving overtakes us, most of the populace is in Christmas mode. It's all about the shopping, decorating, planning how Christmas day will play out, etc. In other words, the majority of the populace has enough on their plates to keep them busy. They don't need to consider doing anything else. Well, if you can manage it at all, you might consider taking a short or long trip between Thanksgiving and Christmas. It's one of the best times to go anywhere if you want some great bargains and want to avoid big crowds.
Weather does play a factor in where you may wish to go. The weather at your destination could be good, tolerable or miserable. But if one travels between Thanksgiving and Christmas, it is sometimes worth the risk. As mentioned, you can get some good deals and have a potentially great time.
I just returned from two days in Las Vegas. Believe it or not, the city is relatively dead until after Christmas. At the airport in May I had to wait in a line of about 150 people waiting to get a taxi. (the line moves quickly). On this trip I walked right to a taxi and boarded.The weather in Las Vegas was decidedly "cool" (under 60 degrees and at night close to 40) but it also meant there were fewer of the street peddlers who tend to try to hand you things you don't want.
On the plane, I talked to someone who found a deal at The Flamingo Hotel: a room for $30 a night. During high season that room routinely goes for about $145 a night. That's just one example of the deals available. Have a hard time in high season finding the slot machines you like, only to discover they are all occupied? Not now. You have your choice. Casino's are as uncrowded as they'll ever be.
The day after Thanksgiving I avoided Black Friday and went to a resort at Avila Beach along the Central Coast. I lucked out. The weather was superb and the crowds almost non-existent. Room prices were decidedly lower than their high season although I stayed at a timeshare property, which is my preference these days.
Years ago my son and I went to Disney World in Orlando in early December and got excellent rates at a Disney-owned and operated Hotel and did not have long lines to wait in. Again, it was a little chilly at times (yes, Florida gets cold in December!) but you just put on a couple of layers and you're good to go.
All, in all, December is a great travel month. I realize that financially it's just not viable for many people because of the costs of Christmas. But if one can manage it, the perks of traveling in December make it well worth the effort!