I've got a Goldshield 5L car cover from carcover.com that I have had on a car for past 6 months outside. Just sold the car, so no longer need it. This cover is designed for outdoors, and is a custom fit. It's still in good shape with just small amount of wear from being outside for 6 months. Cost $180 shipped when I purchased it.
$70 shipped, or $50 picked up in Austin