if you compare vail or park city or aspen to a summit county resort like breck or copper or a basin, by the time march rolls around, the first 3 resorts are already melting, while the summit county resorts are still in the depths of winter. Ive had it happen twice when the last weekend that resorts were open, summit county got like 2 feet of snow. I got to ski fresh powder at the end of april at copper and with the overcast sky you might have thought it was february at a place like park city. Winter just seems to last so much longer at high altitude resorts in summit county.
I wont even talk about a basin, where you can feel like your still in winter with 2 feet of fresh in june.
Driving past vail or park city or aspen in april is like wading through a muddy slushy shithole where all the snow is melting.
Altitude is the answer.