content: I've spent many hours fishing in the summer up to my waste in the lake/stream.    First it cool you off,  the water will cools directly above it by many degrees.  The water will be even cooler than the air, so it will cool your body too. Second, it can give you access to fish areas not accessible from land without the hassle of a boat. Just make sure the lake/stream bed is solid enough so that you don't get stuck in mud.