The average weight of a whole watermelon, such as the kind sold in grocery stores, ranges from 20 to 25 pounds. A 20-pound watermelon contains approximately 14 pounds of fruit. As of 2014, there are over 1,200 watermelon varieties ranging in size from 1 to 200 pounds.
Most watermelon varieties produce round or oblong melons with red, pink, orange, yellow or white flesh. The Charleston Gray watermelon, which is a favorite variety among commercial watermelon producers, has superior disease resistance, produces high yields and is easy to transport from field to market. Several factors affect the size and quality of watermelons, including water, pollination, soil and weather conditions.