Teak holds up well to water and looks great with a light stain, but you might also see if you can find some scrap marine grade mahogany veneer plywood. Marine grade uses special glue that won't delaminate when it gets wet. Check and see if there are any wooden boat builders or restorers in your area, you don't need much and you might get a good deal on some fairly pricy wood.
Properly sealed though most woods will work.