Yes, Turkeys Kayseri Red Tuff can be used for exterior applications in very humid climates. Tuff is a type of volcanic rock that is known for its durability and ability to withstand various weather conditions. It is resistant to moisture, making it suitable for humid climates. However, it is always recommended to consult with a local architect or construction professional to ensure that the specific type of tuff you have is suitable for your climate and intended use.