During our snowy winter months we bring in our patio cushions and store them in the basement. I do believe that this helps extend their life and after 18 years, they just now are beginning to wear down.
But if your basement is full to the rafters, I found this resin storage bin that is attractive enough to sit out on your deck year round. These would keep the snow and ice off the patio cushions but also makes it very easy to grab them when the nice weather comes back.
as seen on Target.com