WOW! On the backside road off Brockway Mtn. Drive along Lake Superior past Eagle Harbor and before Eagle River me and my cousin Steve decided to shed the clothes and go for a quick skinny-dip in Lake Superior. That was on a hot day in August about 15 years ago. Superior was very cold. If I recall correctly, it is one of the coldest, deepest freshwater lakes in the world.
R.I.P. Steve
I swam in Superior once in September which is really about as warm as it gets.