Ok, i'll share my trick for hot weather jump in a fountain - or a shower - or a friend's shower! The trick is no toweling off water after, it cools you down nicely. Repeat as needed every 15 minutes
I was really hoping for swimming beach spots - river beach, or around Tigre, or ?Carilo - but all suggestions here are to go to Punta del Este? Uruguay? is it true? strange, BA is right on water.
I would not step foot in the water around BA its brown and muddy. The nearest beach would be about 5hrs.