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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Showers will largely die away this evening and winds will decrease. Feeling chilly with clear spells. Lows of 3 deg C.
This afternoon will see squally showers- these will be occasionally heavy. Becoming very windy later with gales.
Further one in eight expect to be aged between 71 and 80 years when they finally stop work, according to survey.