Weathering steel is a type of steel which oxidizes naturally over time, giving it an orange-brown color and a rough texture. It has a very high tensile strength, and in spite of its rusted appearance it is actually more resistant to damaging corrosion than standard forms of carbon steel.

The visible oxidized surface is part of the material's weathering behavior. It differs from an applied orange-brown paint finish.

The protective layer reduces further corrosion under suitable exposure conditions. Its effectiveness depends on the environment; the steel is not immune to continued corrosion.