If the sugar spot is large or moist, the fruit may not be fully ripe or could be overripe.
2. Examine a Uniform Color
Ripe watermelons should have a vibrant green color without any spots or bruises on the rind. The skin of the watermelon should be evenly colored, with deep green stripes.
3. Feel for the Right Weight

A good watermelon should feel heavy for its size. Watermelons consist of a lot of water, and the heavier ones tend to be juicier and more flavorful.
4. Tap the Watermelon
One of the oldest tricks to test the ripeness of a watermelon is to tap it gently. A ripe watermelon will create a deep, hollow sound, while an unripe one will sound more dull. The hollow sound implies that the melon is full of water and ready to eat.