Normally at this time of year I expect to wear a wetsuit and a neoprene hat, and still suffer from brain freeze. This weekend (Easter!) I swam in the Thames near Teddington Lock without either, and didn’t suffer at all. After a week of sunshine, I’d expected the water to be tolerable, but it felt warmer than August last year – almost freakishly warm.
Unfortunately I don’t yet have a thermometer so can’t be objective about the temperature, but having swum two weekends ago in 15 degree water, I’m confident it was significantly warmer than that, in April!
Listen to the question from the curious passer-by.