Watermelons are oblong and large, up to 30 pounds. The rind is hard, and dark or light green, depending on the variety. Yellow or golden watermelon tastes the same as red, but has bright-yellow flesh. Watermelons are available from May through September.
Avoid melons with a flat side. The skin should be dull, not shiny. Slap the melon and listen for a hollow thump. Refrigerate for no more than a week.