Seeds planted now this early with snow still on the ground will lie there until the temperature is right for them to germinate. I know lettuce and spinach seed will survive the winter in the ground and germinate in the spring. Some seeds will spoil if left in the cold ground all winter or even for a couple of weeks if the temoerature is not right for it to germinate.
Lettuce, spinach, carrots, peas, cabbage, broccoli, turnips, and all of the early crops have some resistance to frost. They can be planted six to eight weeds before your average last frost date.
My objective here is two fold. One, to go for the earliest possible crop of spinach, and two, dispel the winter doldrums.
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-