Virtually any surface will get too hot on a summer day in full sun. While early composite decks were very sensitive to temperature and did get notoriously hot, any new composite decking will be much more resistant to heat. High- quality modern composite boards don’t become hotter than traditional wooden deck boards. In addition, the lighter the color of the composite deck boards that you choose, the cooler they will stay in direct sunlight. An option to help “cool” it down… is to install a cover for a shaded area.