how cold is it?

I've lived my whole life in cold climates. Here's the way I see it:

30°F ... 10°FseasonalEvery winter
10°F ... 0°Fchilly
0°F ... -10°Fcold
-10°F ... -20°Fvery cold
-20°F ... -30°Fbitterly coldAll winters but one
-30°F ... -40°Fbrutally cold~25% of winters
-40°F ... -50°Ftemperatures that must not be named~10% of winters
< -50°Fnever experienced0% of winters

Temperatures in Fahrenheit because it is a more human-centric scale (i.e., below 0 feels cold, above 100 feels hot).

I've been out at -46°F. If you think you've been out where it's colder, remember this doesn't indicate wind-chill, which is a bunch of hooey. I've skied (at >30mph) at -44°F. According to NOAA, that's -90°F, but that's not how cold works. Cold is tough because it changes the nature of things in the environment—wind chill has no effect on these physical properties.