A whole watermelon stays fresh for seven to 10 days on the countertop. If the fruit is placed in the refrigerator, it lasts for two to three weeks.
If the watermelon is cut, it can stay fresh in the refrigerator for about three to five days. Cut watermelon can last for one day if cut and stored on the countertop. Watermelon is rich in water and electrolytes. The fruit is also high in vitamin A, which is a powerful antioxidant that protects the body from free radicals. Watermelon is also high in lycopene, which protects the skin from UV rays.