It’s really easy to tell if a watermelon is ripe! First off: thumping doesn’t help, and weight isn’t really a good indicator. But that’s okay because the easiest way to tell is by color. Look for a spot on the melon that’s lighter in color than the rest of the rind: this is the spot that was touching the ground while the melon was growing! If that spot is white, the melon isn’t good yet. When that spot turns yellow, the watermelon is ripe!