Short answer: not always, but I wouldn’t just leave it out and hope for the best. Urban outdoor furniture faces winter differently from a suburban patio: balconies, rooftops, courtyards, and sidewalks can get extra wind, rain, snow, salt, and freeze-thaw cycles. Whether it must come inside depends on what it’s made of, how exposed it is, and how harsh your winters get.
If your furniture is truly weatherproof—powder-coated aluminum, stainless steel, high-quality resin, or treated teak—and you live somewhere with mild winters, it can often stay outside with a good cover. But I’d still clean it, dry it, elevate it slightly, and secure the cover so it doesn’t trap moisture or blow around. Cushions, throw pillows, and fabric slings should come inside; they hold dampness and are the first things to get moldy or freeze stiff.
For wood, wicker, rattan, and metal with chipped paint, I’d be more careful. Freeze-thaw can crack wood, rust metal, and break down woven materials. If you have space, bring smaller pieces inside—a balcony storage box, shed, hallway, or basement is fine. If not, use a breathable waterproof cover and keep the furniture off wet ground. Don’t wrap it in plastic; trapped condensation can do more damage than snow.
Heavy snow, ice, salt, and strong city wind are good reasons to move furniture in or store it. Snow load can bend frames, and ice can scratch finishes. In urban areas, theft and vandalism are also worth considering, so lightweight chairs and tables may be safer indoors.
My rule: bring in cushions and delicate pieces; cover and secure sturdy weatherproof furniture; store anything that isn’t designed for freezing temperatures. Check the manufacturer’s winter care advice, and when in doubt, store it. A little effort now saves replacing furniture in spring.