I come from southern Saskatchewan, so I’d guess around -40 in our balmier south. 
Caledon Hills, not far from Orangeville.
When I was a child in Toronto, attending elementary school, we never had snow days either. We also didn’t have school buses. We trudged through whatever the weather threw at us.
Just for fun, when I was older and owned a car, I once measured my route home from my elementary school on my car’s odometer. It came out to 1.1 kilometers, or about 0.7 miles. Since we were expected to go home for lunch (those were “Leave It To Beaver” days, when Moms didn’t work), that was four trips a day, or 4.4 km or 2.8 miles a day. I walked it in all weather, from September to June.
About 2008, dead of winter. I had to travel up from NYC to Montreal for a few days to teach.
I walked about a mile, maybe more, to a local mall because I had no rental car and knew there were the basic chain restaurants at the mall.
It was -12º f not counting the wind. Which was respectable. I had SO many layers on, including 2 scarves wrapped UP over and around my head, and another around horizontally. Gloves, layers, etc.
It didn’t matter. By the time I got to the mall the top of my head was in remarkable pain. Meanwhile, the locals were toddling about with maybe earmuffs. And gloves.
Oh lawdy. That hurt. 
It was 2F this morning(-17C) in N.C. Although we had a -5F windchill about 10 years ago.
20 degrees below zero Fahrenheit. That was in Colorado, a small town west of Colorado Springs. Spent Christmas there one year in the mid-1980s. The local bar was jammed and IIRC giving away free glasses of some sort of delicious Christmas drink.
Nitpick: For all those specifying minus 40 C or minus 40 F, it’s the same thing. The two scales converge at that point.
-35, northeast Ohio, January 1994. I was dating my now-husband and he was on a business trip to Sault Ste. Marie, where it was -45.
I had a 15-year perfect attendance record at my job, but that morning my car would not start. AAA was responding only to people stranded away from their homes, so I called my boss to tell him I would not be in. He said almost everyone else already had called off, so I had to come.
I called for the bus schedule and waited almost half an hour in the -35 for a late bus. We sat at work doing NOTHING for about three hours and the sheriff’s office put out a bulletin that all non-emergency service workers must go to their homes or designated warming shelters and stay there until the travel ban was lifted.
Bus service also was cancelled. I took a cab home cussing my boss all the way. But I did maintain my attendance record for another four years, when I was in intensive care and my husband called in for me. Hah.
Yesterday morning it was -1 F, this morning it is 29 F.
Bam. Cold spell snapped.
I went outside today and the air didn’t make my face hurt!
Yes, -22F is the worst I’ve been in, but it was sunny with no wind. It just had that crinkly quiet feeling of a really cold day, but it wasn’t uncomfortable.