Choosing a ripe watermelon involves looking at several clues together. No outside check guarantees sweetness, so I would avoid treating a shape, stripe pattern, or patch of webbing as proof of the flavor inside.
Look at the field spot
The field spot is the area where the melon rested on the ground. Texas A&M AgriLife Extension describes a yellow patch as a useful sign when selecting a ripe watermelon.
Check the overall condition
Choose a melon with a sound rind. Avoid obvious damage, soft areas, or an unpleasant smell. Ask the seller about the fruit if you aren’t sure.
Don’t rely on one trick
Thumping a melon is familiar advice, but it isn’t a guarantee. The University of Illinois Extension watermelon guide explains ripeness indicators, including the ground spot.
For a shopper’s explanation, read Texas A&M’s watermelon selection advice. Availability and local harvest periods vary, so August isn’t the only relevant season everywhere.
Keep the gathering easy
Choose fruit that suits your plans and follow current food-handling guidance when preparing it. Keep decorative objects off the cutting and serving surfaces.
A recipe card or a photograph can preserve a summer meal memory without needing an elaborate themed display.
Choosing fruit for a summer gathering
Look for a creamy-yellow field spot and a sound rind when choosing a watermelon. No exterior check guarantees sweetness. Use the linked extension guidance rather than claims that a webbed mark or a particular shape proves the flavor.
For the related main guide, read choosing an ornament gift. To keep memories with the decorations, see my ornament storage guide.