I can mine boiling hot into hot jars with lids right out of boiling water. As soon as I snug the band I invert the jars for maybe 10 minutes, then upright them to cool. Once cool I wipe the jars down with a damp cloth so any of the syrup that may have gotten on the jars won’t attract ants, then store them in a dark cupboard or pantry area. I generally eat these pickles within a year. Keep in mind that these shown are only the first batch. I’ll likely make another 4 or so batches thru the summer. These will store for well over a year though.
On a similar note, cucumber slices can be done with the same brine and basic recipe except do not boil and store the pickles in the fridge. For cukes we simply slice them and some sweet onions and salt them in an ice cream pail in the fridge. After a day of salt, rinse well several times, then add the sweet brine that is used for the watermelon pickles, making sure the slices are fully covered with the brine. Cover the ice cream pail and set in the back of the fridge for a week, then dig in.