For twenty years I have been building adirondack chairs. I have always used mahogany. The stainless steel screws used in my adirondack chairs are countersunk and plugged, the way it is done in boat building. I challenge you to find an adirondack chair with these features. That creates a finish that has many saying," It looks too good to leave outside!" But that is what they are made for.
Adirondack chairs should be made from hardwoods, such as mahogany, cypress, and teak. Cedar and pine are soft woods. A friend of mine wanted a chair to match his new deck. I told him cedar is to soft and will not last. Six years later it fell apart. I have mahogany adirondack chairs that are 20 years old.