Cincinnati representing so far in this thread.
Some of the old timers here might remember the Bengals' 'freezer bowl' against San Diego back in, I think '81? I was working 'outdoors' in a beer/wine drive thru. Air temps were at -27 that day, with a wind chill of -56. If I was willing to work
in those conditions, I'd be willing to play
...except for that wind!
I've only been playing a couple of years, but I'm thinking I've definitely played a few times in the teens, on sunny, calm days, and I'm out in like three light layers. Year round play for me. Played this morning at about 35 degrees, and am playing league final round tomorrow morning, with an expected tee time temp of 25.