Temperatures are unlikely to rise above 4
They'll be braving the icy waters up and down the shores of the State, with the best-known diving off at the Forty Foot in Sandycove, Dublin, at noon.
According to Met ╔ireann, rain tonight will finally clear in the south tomorrow morning.
"If you look up at the mountains there might be some snow on Christmas morning," said a spokeswoman. "And there could be some wintry snow showers confined to coastal areas in the north and north-west. But there won't be snow in Dublin."
It will, however, be very cold with polar winds meaning temperatures struggle to reach 4 degrees.
St Stephens's Day will start, again very cold, although the winds will change to a westerly direction, making temperatures somewhat milder, said the spokeswoman.
In such conditions it will pay to stock up on comforting foods. Very few shops will be open tomorrow, with even 24-hour shops closing at some stage.
Most 24-hour branches of Spar around Dublin will close at 10 p.m., reopening early on St Stephens's Day morning.
Details should be available from individual shops today.
Numerous garages, however, will be open at various points throughout the State.
Pizza delivery and other take-away food outlets will close tomorrow, with Burger King, McDonalds and Abrakebabra reopening on St Stephen's Day.
The majority of sit-down restaurants will remain closed until Thursday at least, with one notable exception in Dublin. The Ho Choi Chinese restaurant in Dorset Street will open tomorrow and on St Stephen's Day, with a large contingent expected from the Chinese community.
Many hotels are closing over the festive period, with most reopening on Thursday.
Skeleton staff cover will provide essential services.
Among them will be the staff at the ESB's 19 power-stations, whose services will be necessary to power the thousands of ovens, televisions and Christmas lights, as most of the rest of us sit down to do very little at all.
