Question: When you’re buying whole watermelons, what’s the best way to tell if they’re ripe?
Answer: Watermelon doesn’t ripen any further once it has been picked, so it's worth your while to select it carefully at the store.
To determine if a watermelon is ripe, you should look for two key clues.
First, lift up a few watermelons that are about the same size. The melon you want is the heaviest of the bunch — a ripe watermelon consists of more than 90% water, so the heavier the better, says the National Watermelon Promotion Board.
Second, turn the watermelon over and take a look at its underside. It should have a creamy yellow spot from where it sat on the ground and ripened in the sun, notes the Watermelon Board. If you don’t see this spot — or if it’s there, but it’s a greenish-white color instead of yellowish — it’s probably not ripe enough. Take a pass and move on to the next melon.