It was the day before thanksgiving and the lakes were still open...
I did a solo scuba dive in Lake Calhoun in Minneapolis this morning.
The water temp at 40 feet was 40 degrees. The temp at the surface was 43 degrees.
The two piece 5mm wet suit, hood and gloves kept me warm until I had to do the 2 minute safety stop at 15 feet and could feel the start of hypothermia.