Nearly two thousand people took part in the Great East swim - among them two Olympic swimmers who are hoping to go for gold in the open water events at London 2012.
Russell Hookey spent the day at Alton Water near Ipswich and saw the action:
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Very cold with snow showers and significant wind chill. Temperatures dropping to -3 deg C (27 F)
Tributes have been paid to a 25-year-old man from Essex who was found dead in a river in "unexplained" circumstances.
Feeling very cold and mostly sunny today with some snow showers overnight. Top temperatures reaching only 2 deg C (36 deg F)