So my brother and I were standing out in the cold.
Brother: "Man, it's cold."
Me: "Yeah, it's freezing."
Brother: "Man, it's more than freezing!"
Me: Slightly confused, but perhaps thinking that he might have intended to express that it is colder than freezing, I ask "don't you 'mean less than freezing?'"
Brother: "Nah, man. It's too cold to be less than freezing!"
Me: Yep, he definitely meant that it is much colder. "Well, if it's colder than freezing, the temperature is lower than zero, therefore 'less than freezing.'"
Brother: "Nah, man! Forget numbers! It's about how you feel. And I feel insanely cold. The word "insanely" is more than the word "just", therefore 'more than freezing,' and not 'just freezing' or 'less than freezing'"
Then, the conversation changes topic.
Now I'm left wondering which expression is the most accurate; is it "more than freezing", or "less than freezing"?
For the record, my brother and I were standing out in the West Coast cold, where temperatures don't often dip below zero degrees celsius. At that time, the temperature was five degrees celsius, too warm to be actually freezing. So him even uttering the word "freezing" is obviously a hyperbole. Hence, I'm not surprised why—to his mind—numbers didn't factor in, but instead just the "feeling" of coldness.
So which one of the two is correct?
Best Answer
We say "below freezing"
The usual way to express this is below freezing, which clearly indicates a lower temperature than freezing.
The British National Corpus has 38 results for "below freezing," and none for "more than freezing" or "less than freezing." The Corpus of Contemporary American English has 256 results for "below freezing," and none for "more than freezing" or "less than freezing."
As you say, the temperature is "lower than zero" (if you're using degrees Celsius). We can also speak of temperatures "under zero degrees."
All of the above mainly refers to literal uses of the word "freezing." If you're using it non-literally to mean "very cold," I might prefer to say "colder than freezing," as you do in your title. Note that we would say "colder" than freezing (not "less cold"); this is probably why your brother feels like using "more." However, if your brother just says it is "more than freezing," he may be misunderstood.
People have actually used "more than freezing" both ways
The one example of this phrase I found in the Google Books corpus refers to a temperature above freezing:
(Shermans [sic] Creek: A Redneck Murder Mystery, by Ronald A. Hopkins)
And I found another example using Google search where it is used to mean "above 0 °C":
("Winter Weather Advisory Issued for Tuesday, Warns Commuters of Freezing Rain, Snow, More Rain," by Jesse Wood, HCPress.com)
However, I did also find some people who used it like your brother:
("TOL: I Literally Almost Froze This Morning," Postcards From the Present)
("Day 364: More than Freezing," by Kathryn Dawson)
For this reason, I'd say "more than freezing" is not only unusual wording; it is also ambiguous.
"Less than freezing" might also be ambiguous
In most cases, "less than freezing" seems to be used the way you'd think it would be used: to refer to colder temperatures than the freezing point of water. Examples:
However, I found one interesting example on Google Books where it seems to be used to mean the opposite, although I'm not entirely sure:
(A Journal of Natural Philosophy, Chemistry and the Arts, Volume 1, by William Nicholson)