Full moon to cause strong tides on Christmas Day

Christmas Day swimmers have been warned that a full moon will cause strong tidal streams and increase the strength and speed of rip currents around the Irish coast. Irish Water Safety (IWS), which issued the alert about the conditions, notes it is the first Christmas Day full moon since 1977 and the last before 2034.

Year-round swimmers will know their tides, but charity swimmers may take chances “beyond what is acceptably safe” and find themselves without the strength to climb out of the water due to cold, IWS says.

Cold winter waters can cause “cold shock” and hypothermia, it adds, and even the fittest of swimmers can be affected if there is a high wind chill. “If sea conditions deteriorate, then the charity swim should be postponed or cancelled.” Organisers should provide comprehensive details of events which are going ahead to the Irish Coast Guard or local gardaí.

“It is a fallacy that alcohol will keep you warm when entering the water,” it says. “In fact, it has the reverse effect and could kill you.”

IWS chief executive John Leech said more people would plan to take a charity dip over the Christmas and new year charity season than during the best summer days, due to this year's weather.

It was expected that Storm Eva would have passed through by Christmas Day, but there would still be a residual swell, he noted. Southeasterly winds should make sea conditions more favourable on the west than east coast.

Cope Galway said it was still going ahead as its event coincided with low water – at 10.37am – for Galway tomorrow. However, high tide in Dublin Bay tomorrow is at 11.18am.