albeit a bit off topic...
when i was living in the mid west i had the delightful experience of diving
in may in the haigh quarry providing support / instruction to a group of new divers.
the quarry was colder and darker than diving
the ship wrecks @ 60' in lake michigan.
as a guy who dives in shorts and a rash jersey in 100' of water
... even a 7mm with hood
, gloves and boots was not enough to stave off the cold.
how do those crazy members of the polar bear club do it?