It turns out that you don’t need temperatures below freezing for snow to fall. Snow is a form of ice crystal, and, although it can fall through a layer of air that is above freezing, it does require temperatures below 32 degrees to form in the sky. It’s always below freezing somewhere in the atmosphere; in the summer, that level may be several miles above the ground, whereas freezing levels descend during winter. ADADIn the winter, those snowflakes form closer to the surface, and they have a much easier time reaching the ground — especially when ground temperatures are at or below freezing. If air temperatures are a smidgen above freezing, gradual melting will take place.

Source: Washington Post February 27, 2021 17:25 UTC