DECEMBER could be the coldest on record as large swathes of the country were hit with the second wave of the Big Freeze yesterday.
Snow fell on the west coast, including counties Donegal, Galway and Kerry, with the rest of the country due to be hit today.
And anxious families faced the prospect of not seeing loved ones this Christmas as services from airports across Europe, including Belfast International, were curbed.
Although Cork, Shannon and Dublin airports were open, there were restrictions because of cancelled flights in Europe.
Irish Ferries said there had been a surge in bookings because of restrictions on air travel, which were expected to last into next week.
The increase in bookings came as Met Eireann said temperatures could fall as low as minus 7C over the coming days, with no sign of a thaw in sight.
"Mother nature has become like a wicked stepmother," said forecaster Gerard Fleming.
"A biting cold northerly wind has resulted in snow already falling in the north and west, including Donegal, Mayo, Galway, Longford, Cavan, Roscommon and Offaly. Up to 10cm fell in the north, and snow will hit the east on Saturday.
"That will cause a problem. It's going to stay very cold for the next five or six days. We're more than half-way through December and it's looking like it could be the coldest on record.
"It will get milder, but it might not be before Christmas. There will be more snow after Saturday. There are risks but after Monday it looks like becoming drier."
In 1950, the coldest December on record, average temperatures at Dublin Airport were 2.2C. So far this month, average temperatures have been 0.1C, with the lowest recorded at Mullingar on December 2, when the mercury plunged to minus 10.8C.
There were some disruptions to public transport services in the west yesterday, but the east remained largely unaffected.
However, motorists who left their cars running outside their homes to defrost snow and ice on their windows have been counting the cost.
Gardai in Galway said they were investigating the theft of cars left ticking over in Athenry, Oranmore, and at an estate off Headford Road in Galway.
A garda spokesman said the problem was largely confined to housing estates, but urged motorists not to leave vehicles unattended.
Grit supplies continue to be on a knife edge, with just 13,000 tonnes in stock. Another 26,000 tonnes are due to arrive next week, and local authorities have been ordered to ration stocks and use grit where possible.
Donegal TD Dinny McGinley (FG) said national and local road gritting strategies were a "disaster". The county will salt just 350km of road because of dwindling supplies.
"The response to the present cold snap is pathetic," he said. "Responsibility should be immediately restored to local authorities to provide their own salt and gritting material to meet the demands of their own areas."
Water rationing has continued countrywide, particularly in Dublin, which is subject to reduced pressure at nights.
Dublin City Council said that despite conservation measures, supplies were stretched.
"We have not achieved the savings we needed," said city engineer Michael Phillips.
"Demand is balanced with supply but that's only with restrictions. That (improving supply) can only be achieved if we continue to conserve water.
"We hope not to have any cut-offs between December 23 and 28," he said.