Yes, metal outdoor benches can rust quite easily if left unprotected and uncovered. Exposure to rain, humidity, and morning dew creates the perfect environment for oxidation—the chemical reaction that causes rust—especially on metals like standard iron and steel. However, not all metals are equally vulnerable. The rate and severity of rusting depend heavily on the specific metal, its protective coatings, and your local climate.
To answer your concern directly: an uncovered bench made of untreated carbon steel will likely show rust spots within a single season in a damp climate. Conversely, benches made from inherently rust-resistant materials like aluminum, stainless steel, or galvanized steel can withstand years of exposure with minimal corrosion. The key is the material's ability to form a protective barrier against moisture.
You can significantly extend the life of any metal bench with simple, proactive steps. First, choose wisely: opt for aluminum for lightweight, zero-rust durability, or powder-coated steel for a colorful, protective finish. For existing benches, applying a fresh coat of outdoor-rated paint or a clear sealant can shield bare metal. Regular maintenance is crucial; wipe down your bench periodically to remove moisture and debris. While not always aesthetic, using a waterproof cover during prolonged wet seasons or winter offers the best physical protection. Placing your bench in a partially covered area, like under a pergola or wide eaves, also dramatically reduces its constant exposure to the elements.
Ultimately, while rust is a common threat, it is not a foregone conclusion. By selecting the right bench material and committing to minimal seasonal care, you can enjoy a durable, rust-free outdoor seating area for many years without the constant need for covering it.