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.