Forecasters say the coldest February in five years could cause travel disruption and problems with frozen pipes next week.
'The Beast from the East' - a cold blast of air driven from Russia - will bring plummeting temperatures and the possibility of heavy snow from Tuesday.
There is already a low temperature warning in place for tonight (temperatures will drop as low as -3C), and an exceptional cold weather advisory for the week ahead. Air and ground temperatures will be 5C to 10C below normal from tomorrow, with significant wind chill and penetrating severe frosts, Met Éireann has warned.
Snow showers, mainly affecting eastern areas on Tuesday, will progressively become more widespread and heavier through midweek, with significant falls expected.
The AA's Barry Aldworth says motorists should be preparing already. He said: "If your car has been sitting idle since Friday evening, do check it as this cold weather can affect your battery. If you check it this evening, you'll hopefully not wake up on Monday morning to a car that won't cooperate."
Here comes the #beastFromTheEast into this coming week. Some areas of NW #Europe could potentially be cut off from #snowfall It’s going to be #ExtremeCold potentially record breaking... so stay tuned for updates. Via @meteociel #Travel pic.twitter.com/qR6sbc3Wvp
— WEATHER/ METEO WORLD (@StormchaserUKEU) February 23, 2018
The Government's National Emergency Co-ordination Group on severe weather will meet tomorrow morning.
Winds sweeping across Siberia from the North Pole will bring sub-zero temperatures and biting winds.
"They'll be a few flurries tomorrow afternoon, Monday, but they won't amount to very much," said forecaster Pat Clarke.
"But during Tuesday we'll get sleet and snow showers developing along the east coast.
"And then as we go into Tuesday night, Wednesday, Wednesday night into Thursday, the snow will become more widespread across the country, and there will be more significant and potentially disruptive accumulations at lower levels.
"Eastern areas will obviously get the worst of it, and get it initially as well. Areas further to the west - Connacht, west Munster - they will get some, but it will be a gradual process for them."
Freezing air from Russia is pushing a cold front ever closer to Ireland.
Temperatures dropped as low as -3C overnight across parts of Leinster, Cavan, Monaghan and Donegal.
Met Éireann has issued a yellow weather warning for exceptionally cold weather for the remainder of the week.
Met Éireann has a Weather Advisory in place for all of next week into next weekend for cold temperatures, with snow showers from Tuesday.
— Met Éireann (@MetEireann) February 24, 2018
There is also a Status Yellow warning valid for tonight for Low Temperatures in Leinster & parts of Ulster
Latest info https://t.co/X6NncUghZ9 pic.twitter.com/UYuQ1HNQyy
Snow showers are expected from Tuesday onwards - particularly in the east and southeast - with the possibility of more persistent bands of snow developing later in the week.
Barry Aldworth from AA Roadwatch is urging motorists to take extra care.
"We may have been thinking up until now that winter was behind us, but it looks like this week we're going to get a little bit more," he said.
"Unfortunately this weekend so far has been quite a bad one on the roads in terms of accidents, with injuries and fatalities across the country.
"So definitely we want motorists to heed the warnings - slow down, take extra precautions and make sure that you get home safely."
Farmers are being warned not to be caught out - water supply could freeze and early lambs will need to be kept indoors.