Around here, I see some co-workers commute in the winter: about -5C to -10C, or about 14F to 23F. The other week, I was out riding and it was about the same.

I grew up in Edmonton, Alberta though, and I remember classmates in university showing up after riding from the place they were renting. That was typically -20C or -4F, often with hard packed snow - never mind the wind chill. Now that would be pretty cold on a regular basis.