Here in coastal South Carolina, local melons have been filling our markets.
But, how to tell if one is ripe and ready to cut?
For watermelons, look to the skin to see if the melon is starting to turn more yellow. Then make a fist and thump the melons in the storage bin. Move then around as needed. A ripe melon has a deep satisfying sound, not a sharp higher sound. You will be able to tell the difference immediately when you thump a ripe melon. Sometimes I go through a number of melons before I hear that deep sound. Also, inspect the melon to make sure it is not overly ripe so that it has too-ripe places starting to soften on the outside–which is more easily seen with cantaloupes.
Look at this gorgeous, deep red, sweet watermelon!

Cut whatever melon you have bought in half and then into slices. Take a small knife and cut away the rind of each piece. Then, cut the half-round pieces into bite-size pieces. For a big melon, I often just cover the top of the uncut half and store it in the refrigerator until I am ready to cut it up. It stores better that way.

I store my cut pieces in a covered glass container in the refrigerator.

What a gift these local ripe melons are!
Enjoy!