We strongly suggest not leaving the board out of water in direct sunlight, because as the air heats and expands it can stress the board's seams. This occurs when a board is left fully inflated and out of the water. When you actively use an inflatable SUP board in the water, the water cools the board down so this does not happen. If you must leave the board out of the water and inflated, let some of the air out of the board to allow for the expansion of hot air within the board.