I read this today in a magazine: “… A glutton for punishment, the CEO also enjoys running in sub-freezing temperatures…”
Sub-freezing? Google gave me 176,000 hits.
The American Heritage Dictionary prefers it without the hyphen.
Sounds fine to me. The sub- prefix means “below” or “beneath”. Sub-freezing just means below freezing. Why would you think it’s not proper usage?
Merriam-Webster’s Collegiate (11th ed., the most recent) has it sans hyphen, dated 1949.
I guess “infra-freezing” just never caught on, like you’d think it would.
Sounds fine to me too, and less ambiguous than “sub-zero.” (I’m never sure whether “sub-zero” means “sub-freezing” or “below 0[sup]o[/sup]F”…)
It sounds fine to me. It makes it clear the person runs in weather below 32 degrees, not just plain chilly weather.
Why wouldn’t it sound correct?
Based on other posts in this thread, I’m beginning to suspect the OP is objecting to the use of the hyphen, not the term itself. IMO, it’s still acceptable, if somewhat dated, usage.
I’m more used to “sub-zero” but it sounds reasonable enough to me.
I always took sub-zero to mean sub-freezing or below 0°C.
Round these parts, sub-zero means below 0 F. And yes, people run in those temps.
There’s nothing wrong with the expression. Saying ‘sub-freezing’ avoids the possibility of confusion between below-zero Fahrenheit and below-zero Celsius when the temperature scale is not specified, if what you really want to say is ‘below freezing’.
Also, as a compound adjective, the expression ‘sub-freezing’ is much clearer with the hyphen.
I’m back. How do freezing temperatures differ from sub-freezing?
Can temperatures be below freezing? A temperature of 20 degrees is freezing, so what would sub-freezing be?
Hmm. Never thought of it that way. To me, ‘freezing’ means ‘at the freezing point of water’, 0C/32F. If you place water in a much colder environment*, it always actually freezes at 0C, doesn’t it, no matter how much colder the resulting ice is going to get? In other words, there is never any actual liquid water at temperatures below zero Celsius?
[sub]*At standard pressure (101.3 kPa, or whatever it is). No tricks with high pressure, eh?[/sub]
The water that puddles on ice floes is liquid below 0°C, because the ice is less saline than seawater, the liquid on the floes has more concentrated salinity, keeping it liquid below what would be the freezing point under standard conditions.
No, a temperature of 20 degrees (Farenheit) is already frozen. Any freezing that’s going to happen, has already happened. At least, if we’re talking about fresh water. There’s some solution level of saltwater which would be freezing right at 20 F, but then, there are non-water substances which will freeze at any temperature you care to name. Fresh water is, I think, implicit in referring to a temperature as freezing.
But no one says “frozen temperatures.” It doesn’t make sense. “Freezing temperatures” implies that it’s cold enough to freeze water, but leaves open the actual thermometer reading below 32 F.
Again, I concede. May my challengers sub-freeze in hell. 
Would it sound right to say “Sub-freezing wins…fatality”?