Ten minutes ago or so, I went outside with the dogs and there was little discernable difference in temperature from inside. It was definitely more humid, and perhaps even a bit warmer. I was just outside again (Lilli Munster likes me to go with her and usually won't go out without me unless I leave the door open) and it has dropped at least 20 degrees.
Five minutes later, eb leaves for work, and she poked her head back inside to say, "Okay, it's fucking cold out here now..."
So for the next few days in Houston, it's winter. Pay attention so you don't miss it.