Or leave the windows closed for that matter....
Back to the topic.
If you decide not to use your car while it's snowing be sure to clear the snow from the rear window every now and again.
Missus's Punto sat through the snow a couple of years ago and come the thaw we discovered the weight of the snow had snapped the rear wiper clean off.
I always clean the snow off where possible. You don't want it thawing and refreezing as dense ice.