The temperature in our basement, where I spend a lot of time doing little projects and drinking coffee, is just below 60°F on a cheap thermometer placed at eye level. That is barely comfortable most of the time to be nude but then I'm not exactly all that active down there. Outside right now, it's about 28°F, well below my comfort level for more than a few minutes.
I have hiked nude, however, in temperatures that were probably in the 50s and it's bearable. But my skin did feel cool, maybe even cold, to the touch. That's also true when I'm nude in the basement. I'm wearing shoes and socks, though, and that makes a big difference to me. Nevertheless, I can still be fairly comfortable if I'm active enough. It's hard to say ow much is "enough," though. Under any conditions, when I go out for a long walk, I will be much warmer when I get back than when I started, which seems logical enough. In freezing or near-freezing weather, though, on, say, a two-mile walk, my hands will be cold until I've finished the first mile. My feet are perfectly fine but my face stays chilly the whole time. So much for "face all over." Sometimes, I've been out in cold, snowy weather and eventually my hands warm up enough to remove my gloves.
Another curious thing is that when I've been nude indoors and been fairly comfortable in a cool house, when I've gotten dressed at last, mainly to go outside for the paper, I am chilled for a few minutes by my cool clothes, until I get them all warmed up again with my body heat. I have seen it mentioned that if you have trouble staying warm in the winter, you probably aren't eating enough of the right foods.
Some of the coldest times I've ever experienced were when I was in the army in Germany, standing around outside waiting for something (you spend a lot of time standing around and waiting in the army), and could not stay warm for anything. I recall one occasion when we were having a vehicle inspection. I was standing next to my Jeep (which was a Ford), hood up and everything and it started snowing. I don't remember what happened next.