Four degrees: the shortest swim of the year, timed to the second
The thermometer read 4.2 °C off the end of the jetty at eight in the morning, the lowest I have recorded at the lake, with a skin of ice in the reeds and frost on the pontoon boards. There were four of us. We had agreed the time before getting undressed, which is the rule: three minutes, out together, no heroics. My swim, by the watch on the bank, was two minutes and forty-five seconds.
The first thirty seconds in water that cold are the same every time and never get easier, only more familiar. The breath goes out of you in a gasp as the skin registers the cold, and then the body wants to breathe fast and shallow, which is the cold shock response and is the thing that drowns people who fall in unexpectedly. The whole skill, as far as I have learned it, is walking in slowly, up to the waist, up to the chest, letting the gasp happen with my feet still on the bottom, and then breathing out long and slow, on purpose, three or four times, until the breathing is mine again. Only then do I push off and swim. Pushing off before the breathing settles is the mistake I made the first winter, and I remember swallowing lake because of it.
Once the breathing is under control there is a minute or so that is close to wonderful: bright, sharp, every sense turned up, the water feeling like a solid thing to move through. Head up, breaststroke, face dry, because at four degrees the face in the water sends the heart rate somewhere I would rather it did not go. Then the hands. At about two minutes my fingers started to lose feeling despite the neoprene gloves, and that is my signal: hands going is the body telling you it has begun to triage. I turned at the second buoy and came back.
Out at two forty-five, hat already on, and the dressing routine from the card. The skin was bright red and stinging from the knees down, which the boots do not prevent, only soften. Shivering started at about ten minutes and lasted twenty. Tea from the flask, a walk to the car park and back, a second cup. Fine by half past nine.
A rough rule I use and do not recommend to anyone else: about a minute per degree of water temperature, and never more than the time agreed on the bank before anyone gets undressed. At four degrees that is a short swim. In February the whole point is that it was a swim at all.