Many years ago, someone who seemed like they ought to know told me that it cannot snow below a certain temperature.
I’ve lived in Florida for many years so this factoid doesn’t come up in conversation, but on a recent visit to Pennsylvania I repeated this bit of wisdom to some of the locals and none had ever heard of the idea, and most felt free to tell me I’m nuts. These were reasonably smart folks I was dealing with, so now I’m wondering if this is baloney.
So … is there a certain temperature below which it cannot snow, and if so, why?
No. Snow can happen at any temperature below freezing (and even a little above).
There is a saying that a certain day is “too cold to snow.” There’s a certain amount of truth to the saying, but it’s not a literal rule.
However, generally, in order to get an especially frigid temperature in the US, you need to have clear skies to the heat of the Earth will radiate off. Obviously, if you have clear skies, it’s not going to snow.
In addition, very cold air holds less moisture, so any snow is light and fluffy and not enough to be an issue.
The saying recognizes these facts. But it does not mean that it’s impossible to snow a very low temperatures – see March of the Penguins, for example.
For a second I thought this would be the first question that I’d get to provide the first answer to. Silly me, this is The Straight Dope! Good work all.
Thanks so much for the replies and links! Reading over the material helped me recall the source of my information. When I lived in Montreal about 30 years ago we had an arctic blast come through that sent the daytime temperature down to 40 below for several days. The weathermen (to whom we were paying VERY close attention during that period) were saying that it was too cold to snow. And, from my reading of the links, they were pretty much correct.
So that’s why those Pennsylvanians thought I had a screw loose. They have probably not experienced such frigid temperatures.