Is it too cold to snow?

Dear Tom,
We’ve all heard the old saying, “It’s too cold to snow.” That’s not true, is it?
Jerry Jones, Chicago

Dear Jerry,
No. Earth’s atmosphere can never be too cold for snow to fall. All that is needed is water vapor in the air – and some is always present, even at very low temperatures – and a mechanism to cool the air below the saturation temperature. Antarctica satisfies both conditions, and the ice cap is clear evidence that snow falls there at freezing temperatures.

Direct observation confirms this. Ice crystals and light snow were observed at the South Pole station with a temperature of 70 degrees below zero. Even in Chicago it was snowing and bitterly cold at the same time. On January 10, 1982, Midway Airport saw 0.8 inches of snow with a temperature of 15 degrees below zero.