weather

2. VERB

If something such as wood or rock weathers or is weathered, it changes colour or shape as a result of the wind, sun, rain, or cold.

• Unpainted wooden furniture weathers to a grey colour.     
• This rock has been weathered and eroded. 

weathered ADJ:

• The facade of the building was a little weathered.     
• The man had a worn, weathered face.

... Cobuild