How cold can it be to snow?

It's typically near freezing or not too far below. When you get below 15-20 degrees F, it becomes difficult for the air to hold very much moisture, so if it snows it will not generally snow heavily.

But under certain conditions it can snow at a few degrees above freezing, though it rarely sticks to the surface. It is possible to snow when the temperature is in the 40's, but this requires unusual atmospheric conditions and rarely lasts long.