So it has been cold here this week. Today’s high is forecast to be 20 degrees, but it feels all of 4. My first thought was “bitter cold” but then I recalled the Polar Vortex.
So at what point is cold weather “bitter”?
My rule of thumb:
Zero or below is cold.
Minus 20 or below is bitter cold.
Minus 40 or below is stupid cold.
F or C? For me, under about 35 F (above zero) is “cold”. Under 15 or so is bitter cold. Single digits and below is freezing (and I’ve never personally experienced any worse than about -5 F, which would have been druing a winter in Maine while I was in the Navy).
Anything below 25 F is bitter cold to me; I’m a warmie.
I’d say 0F with windchill is bitter cold, as I experienced approximately that in a blizzard 10 or so years ago and it was too cold for me to walk against the wind since I only had a winter coat but no hat.
Converting that to Celcius, I agree completely.
(Of course -40 is the same in both scales.)
Yeah, like Quadgop, I wouldn’t consider it bitter cold until it’s -20F. I have snow 6 months out of the year, so pretty used to it.
I’d say that 20F is “cold” for me because, while I don’t have a bodily reaction to it and indeed it can seem quite temperate given enough clothing, the wiper fluid in my car, and any water I might be carrying with me, don’t agree with my subjective assessment. I once ran 40 miles around Canandaigua Lake in 20 degree weather and except in the beginning I never had to use the entire combination of the zipper on my winter coat, gloves, and hat, but the water bottles I brought along froze.
I live in the South, but I have spent time in Arctic climes, and have had a lifelong preference for cold weather. As such, I have trouble assigning a number for this, because I think it’s rather subjective. As a starting point, though, “bitter” describes things that are “sharp” or “cutting” (among other things) and is etymologically related to “bite”. (Indeed, we say that a cold wind has a “bite” to it.)
So, a “bitter cold” is a sharp, cutting, biting cold. To try pin that down a little further, I would say that the temperature has reached that point when dry, still* air causes a stinging, painful sensation in exposed skin no more than 30 seconds after transition from a warm environment.
Flipping back through my mental file of times, places, temperatures, and wind conditions, I can state that, for me, that point is definitely below 10F, probably below 5F, but no lower than -10F.
*Wind, of course, blows this all to hell. A wind can bite even when the temp is well above freezing. Breathing, for the record, amounts to roughly a 3 mph wind, so the nose should not be used to gauge a still-air response unless you’re holding your breath.
0F with appreciable wind (like 10 mph) is about where bitter cold starts for me. The wind makes a big difference. When it was -14f here a few weeks ago, it didn’t seem that bad to me, but a few days later we got single digits with significant wind and it was awful.
I’d go with that. I stop running outside at around 0F. But I’ll hike to -20F, or at least I used to. Nowadays I’m getting pretty soft. I’ll rarely ski at or below -10F; I’ll find better things to do.
For me, it depends on the wind. Zero and calm is no problemo, but 20 and a howler that cuts right through anything you are wearing is pretty bitter in my book.
10C is cold
0C is bitter cold
-10C is “not leaving the house” cold
If Clan Piper followed that approach, we’d starve by mid-January as the food ran out. 
(Had to walk to work in -40C last month because my car battery froze.)
For me, bitter cold would be when you go outside, inhale through your nose, and the inside of your nose freezes. I expect that’s dependent on the individual, so exact temp will vary.
Bitter cold for a prairie boy is -30 C.
But it really depends on the wind. A windy day at -10 is pretty bad.
Yeah same here. I’m from the snow belt and built like a polar bear but when it’s cold + windy, it does suck. Today I was out and it was 20-some degrees (F) but where I had to go it was windy as fuck. Windchill was 4 in the city but this area was particularly windy. I’d say that was bitter cold right there.
I’ve stood in my yard on a day with hardly any wind and -10 temps and it’s fine, compared to the wind today.
I know this one. I lived in Montana when I was a young guy and could take the cold. My rule was: If my mustache froze solid the instant I walked out the door, then it was pretty cold. If my mustache didn’t freeze, it just wasn’t that cold.
My rule is similar. If my nose hairs freeze, it’s bitter cold. That generally happens right around 0 degrees F.
Yeah, I would agree with that.