The thing is (for those of you who don't already know this), I live on the Gulf Coast - currently in the south suburbs of Houston, and before that I lived in Galveston, right on the water, for many years. So my experience of winter is a bit different than many of yours. But we do have different weather in the winter - you can still tell it's winter, if you know what to look for. Today, on the first day of winter, it's chilly, but not terribly cold - my phone tells me that it's 46F. That's pretty cold for us by daytime standards, but the wind's not blowing and it didn't feel especially cold to me.
I noticed last night that some of my neighbors had their plants covered, but they have tended to be conservative about that in the past. I don't think the temp was below freezing last night. (I hope not, because I have a Norfolk pine that I have had for years and would like to keep!) We normally only get a handful of days where there's a hard freeze, even here 20 miles inland, and Galveston gets even fewer. In fact, my doctor told me when I went in about my sinuses the other day that this was a particularly bad year for allergy-sufferers because we never had a hard freeze last year - although I'm pretty sure I remember several light ones.
Some trees have lost their leaves now; others still have quite a lot. We've had a relatively colorful fall, by our standards; the tallow trees in particular (which grow like weeds anywhere they're allowed to) have been very bright. Whatever fall color we get doesn't come until November or December, but this year we had a pretty substantial cold spell in early November that was enough to get us a good bit of color.
Any time after, say, the middle of October, it's not unusual to get some cold weather - in fact, some year we'll have more really cold weather in the fall than we do in the real winter. We get "blue northers" (and the sky really does turn blue) where a cold front comes pretty much out of nowhere, if you haven't been watching the weather reports, and the temperature drops about 20 degrees in just a few minutes. Surely that's not really only a Texas thing, but maybe it's more noticeable down here because it's usually warmer to begin with. Really, we can have shirt-sleeve weather off and on throughout the winter, although it's only towards the end of the winter (meaning, y'know, March) that it becomes common. I'm looking at the phone again, and it says it's supposed to be 79 on Sunday and 70 on Christmas Day, but Christmas night it's supposed to get down to 34. That sounds like we might be getting a norther for Christmas, actually.