In my area at the Jersey shore, there are a number of midwinter "Polar Plunge" events, fund raisers for various charities. About 5,900 participated in the Special Olympics one at Seaside in 2012.
My son did the plunge when he was 13. It was cold! I probably shouldn’t write this but I had to laugh at how many of the men announced LOUDLY “no remarks, ladies... this is really COLD water!!”