"I knew the way you know about a good melon," so says one half of a fictional elderly couple in the rom-com classic "When Harry Met Sally." The quote is about knowing when someone is your other half.

The first tip for getting the perfect watermelon is to buy it in season. In the U.S., the fruit is harvested in the summer months, although the region might dictate when it's at its peak. For Rebekah ...