There are, in fact, a number of things you'll want to consider before your making your purchase to ensure your new outdoor furniture cover will keep your furniture looking brand new as long as possible.

Make Sure It's Thick Enough to Keep Out UV Rays
While harsh weather certainly takes its toll, the biggest threat to outdoor furniture is actually the sun. Harmful UV rays fade colors, turn some materials dry and brittle, and can degrade fabrics. That being the case, it's important that you purchase an outdoor furniture cover that is thick enough to eliminate sun damage altogether.

Is It Waterproof?
Sounds like a no-brainer, but you'd be surprised how many outdoor furniture covers are just "water resistant." These covers perform well in a passing drizzle, but if they get hit with an all night thunderstorm or a six-inch snow that sits on them for weeks or months, they actually soak up the water and end up doing more harm than good. A waterproof cover will repel water completely so that there's no chance of water damaging your outdoor furniture whatsoever.

Durability and Thickness
These qualities go hand in hand. Keep in mind that your outdoor furniture covers get whipped around during large storms and high winds, and if they're not built solidly enough to withstand the punishment they will fray and tear, especially when placed over furniture with sharp edges or corners. Also, don't forget that your furniture cover is going to be taking the beating from the sun, rain, snow, sleet, and wind that you're saving your furniture from. In that respect, it doesn't pay to cut corners when it comes to buying thicker material and a furniture cover material that is guaranteed to last.