Some years later on subsequent business trips I was prudent enough to dip a finger into Lake Michigan (Boyne/Harbor City) and Lake Superior (Duluth).
I took a quick dip in Lake Michigan at the Indiana Dunes National Lakeshore late summer after graduating. Damn near burned my feet off traversing the scorching dunes. The cold water felt good on my feet, but not so good on the rest of my body when I dove in.
At the end of my first summer in MN (Labor Day '78) I was camping with friends on the north shore of Lake Superior. After three days with no showers to clean off the hike produced sweat and the smoky stench from sitting around the camp fire, I decided a dip in the lake was in order. It was the end of summer and the water was shallow at the shoreline so it HAD to be warm! [I'd been living in Miami before that.] Another newbie southern boy from Tennessee decided to join me. The "locals" just shook their heads and gathered around to watch the show.
We didn't bother testing the water and just dove in from a rock outcropping. Well, the water WAS warm by Lake Superior standards. It was 45 degrees and not 42. I practically hydroplaned the 100 yards to the beach.
At least I have a story to tell. Along with my cross country skiing excursion at 38 below – probably 45 below with wind chill a few years later.
I haven't been fool enough to do either again. With age comes wisdom and wussiness.