Snow is being forecast for eastern counties from Sunday evening.
Very cold weather is expected over the weekend but particularly from early next week, amid warnings we could see a 'significant snow event' similar to 2018's Beast from the East.
Local authorities are already planning for severe weather, with the National Directorate for Fire & Emergency Management monitoring the situation.
While the scale of any such snow event is not yet clear, a wind chill of -6 or -7 degrees is expected from Monday morning.
Ahead of the cold weather, Met Éireann has issued a weather advisory for the entire country from Sunday through Wednesday.
Forecasters say: "Sunday, Monday, Tuesday and Wednesday will be very cold with temperatures in low single figures by day and with sharp or severe frosts and icy patches at night.
"Showers of sleet or snow at times in eastern counties from Sunday evening onwards."
They're also warning of hazardous conditions on roads and paths as a result.
Alan O'Reilly from Carlow Weather earlier told Breakfast Briefing that we're definitely set for the coldest spell we've seen this winter.
He said: "The uncertainty is around the significant snow event... Wednesday into Thursday.
"It's very difficult to call that at the moment - we have basically very cold air arriving from the east.
"The temperatures will start to drop back really from tonight, and by Sunday we're going to have a wind chill that's going to make it feel bitterly cold."
Mr O'Reilly said there's still uncertainty in the weather models, as they show different scenarios - some showing significant snow event, but others show snow turning to rain.
However, he said there's "no doubt about how cold it's going to get" over the coming days.
