Whether you can leave metal urban outdoor furniture outside all winter depends heavily on the specific metal, its protective finish, and your local climate, especially exposure to salt air. Salt air is highly corrosive because salt accelerates the electrochemical process of rust on ferrous metals like iron and steel. Moisture and salt combined create a perfect storm for deterioration.
Not all metals are equal. Aluminum is an excellent choice for coastal areas as it forms a protective oxide layer, making it highly rust-resistant. Stainless steel (particularly grade 304 or 316) offers strong resistance. The real vulnerability lies with ordinary steel, even if painted. The key is the protective coating. A high-quality powder coating provides a durable, bonded shield far superior to standard paint. Regular galvanized steel also offers good protection.
To minimize risk, choose powder-coated aluminum or stainless steel. Apply a automotive or marine-grade paste wax to coated surfaces in late fall. Cover furniture with breathable, waterproof covers, and elevate it off wet surfaces. Inspect and touch up any coating chips immediately. With the right material choice and proactive care, your metal furniture can withstand winter's harsh conditions.