I've heard of the snow trick and tried it. The seed will wait till the soil warms up to germinate. I've just done in on a small patch to overseed and can't say there was much success. The trick is to get it into the soil on a uniform basis. The seed just sat on top and washed away. There may have been a few seeds that came up but I still ended up working the ground and seeding it like normal.
If you are trying to do a whole yard, I doubt it will work. Most of the seed will wash away and be a waste of money for expensive seed. The best time to plant is fall anyway. Work the ground, use a broadcast spreader, and keep it damp.