My point is our environments used to drop in temperature when the sun went down, which was part of what controlled our circadian rhythm. We can still replicate this today, though, by turning the temperature up in our houses during the day and then down at night. Smart thermostats are great for that kind of thing, too, so you don’t even have to think about it. There are a lot of studies that say that 68 degrees is the magic number for sleeping well, but play with it and see what works for you!
It really makes sense when you think about it. Years ago before air conditioning, the temperature dropped at night. Now, though, we live and work in temperature-controlled buildings with nice, comfortable, temperature-controlled cars to sit in while we travel between them (except for us Jeep people. We like to think we are immune to weather).