As some of you may know, I live in a house with no insulation (no, I'm not exaggerating, it's just a very old house) and a poor heating system. A few times in the cold months so far I've been able to see my breath in my own home! When I woke up this morning and found it snowing, but my house warmer than usual, I wondered why. Here's the answer:
Very cold air can't hold moisture. The water vapor that remains in the air becomes frost, evaporation is reduced, and humidity remains low. When the air is warmer and more humid, like the 23 degress it is today as opposed to the -7 (with wind chill) it was yesterday, it can hold moisture which can turn into snow. Precipitation is possible and, as we all know, the freezing temperature of water is 32 degree farenheit, so the precipitation that results is snow (not rain). So, in fact, it's not the snow that makes the air warm, but the warm air that makes the snow possible.
(I got my answer from this site: www.coolquiz.com/trivia/explain/docs/snow.asp. To verify my facts, I checked other sites too, but this one is the most friendly to the non-scientific mind. Plus there is a cute cartoon guy bundled up and looking confused, so I liked it immediately.)