One of two broad categories of melon (the other is muskmelon), watermelon is native to North Africa. Though there are many varieties, the elongated oval-shaped, green-rinded version averaging 15 to 35 pounds is the well-known summertime treat in the U.S. Other varieties have flesh that ranges from white to yellow to pink.
June - October
Look for firm symetrical melons without cuts or dents. A watermelon should feel heavy, its skin should have a nice sheen, and the underside (the side which grows against the ground) should be pale yellow. They should sound hollow when thumped or slapped if they are ripe. An abundance of small white seeds means the melon is immature. In addition, feel the stem end. If it is smooth, the melon gave up the stem easily because it was ripe when picked. If the stem end is rough, that means that the melon wasn't quite ready to be picked and was torn from the stem.
Refrigerated for no more than one week. Cut slices should be tightly wrapped and used within a day or so.