So with basically three areas of the country where you can expect to stay reasonably comfortable during January and February, being South Florida, southern Texas, and in the desert Southwest, which of those areas is the best? And as you might've suspected the answer is.... it depends.
Where you might want to park your RV during the winter has a lot to do with how you live in your RV. If you are an RV Park kind of person, or happen to be a boondocking kind of RVer you can stay in either of those three areas. But if you like to boondock for a majority of the time then far and away the place with the most boondocking opportunities is the desert Southwest.
Temperature is not the only reason RVers choose one area over another, a very common reason is humidity. I have lived in the most humid area in America, Miami Florida, I know there are other very humid areas around. But Miami is the only place in the continental United States that has tropical rain forests, and that's about as humid as it gets, and don't get me started on the bugs. I've also lived in very dry areas and I can say without a doubt that no matter what the temperature is, low humidity is more comfortable. So if you want relatively low humidity you can forget South Florida. And in Texas you at least need to stay away from the coast. Or you can go to the desert Southwest where it's...... a desert.
There's also social aspects to where RVers like to stay in the winter. If you like to be around a lot of people, and associate with bunches of people then all three of the popular winter places offer ample opportunities to be as close to people as you want to be. But having lived in the South and the West, I believe that the desert Southwest has more locations and opportunities to be as far away from people as you want to be. Which is very important if you've ever boondocked next to me for a few days you want to be able to move as far away as possible.
How much it cost to live is also very important. It's hard to say exactly if one area Is way better than the other in terms of cost-of-living but I'm relatively sure of this, South Florida is expensive. Some of the RV parks border on ludicrously expensive, and boondocking is hard to come by. Texas doesn't seem too bad, there's some boondocking available but not all that much, but the long-term RV Parks seem fairly reasonable. There again if you're a serious boondocker it's hard to beat the desert Southwest for being able to live relatively cheap, mainly because free boondocking is available almost everywhere you go.
Now there's a lot more to which area is the best for winter RVing, but like I said in the beginning it all depends on how you want to live and its hard to get down into those kind of details in a short blog post. But for me personally with my love of boondocking the desert Southwest is almost perfect. I can get as far away from people as I want, or go to Quartzsite and be real close to everybody. The ability to boondock wherever and whenever I want, keeps my living expenses within reason. There's seldom a tree to block my solar panels. And the very low humidity makes even chilly weather easy to deal with.
The desert Southwest in the wintertime may not be paradise to everyone but to me it comes pretty close.
Lone Tree BLM boondocking area, Lake Havasu Arizona