Motorists are being urged to slow down and take care as temperatures are set to plunge again overnight.
Met Éireann said freezing fog, which will be dense in places, would persist until late on Monday night leading to “very hazardous” driving conditions.
The forecaster issued the warning for Connacht, Carlow, Dublin, Kildare, Kilkenny, Laois, Longford, Louth, Meath, Offaly, Westmeath, Cavan, Donegal, Monaghan, Clare, Limerick and Tipperary.
People have been warned to take extra care on the roads over the coming days and to check on the elderly as temperatures could drop well below freezing.
Very cold on Tuesday with freezing fog patches over the N half of the country in the morning. Frost & ice will persist through much of the day 🥶❄️
Mostly cloudy in the S half of the country with rain pushing into the SW, falling as sleet or snow in places 🌨️
Highs: -1 to +4°C. pic.twitter.com/dF37NaFEXS— Met Éireann (@MetEireann) December 12, 2022
On Sunday morning, the National Emergency Co-ordination Group convened to discuss the effects of Ireland’s first cold snap in recent years.
The group will meet each day this week to provide advice.
Met Éireann said temperatures fell below minus 5 degrees in many areas on Sunday night.
The lowest temperature of the year so far, minus 9 degrees, was recorded in Katesbridge, Co Down in the early hours of Monday.
Temperatures plunged to minus 8 degrees in Athenry, Co Galway, while Mount Dillon in Co Roscommon also recorded a bitterly cold low of minus 7.4 degrees.
➡️❄️ Today was provisionally the coldest day at our weather stations since 2010 ❄️⬅️ ⤵️ https://t.co/HbdvpC4eox
— Met Éireann (@MetEireann) December 12, 2022
The average from Met Éireann’s network of 25 monitoring stations showed Monday was “provisionally the coldest day since 2010.” The maximum temperature across the network was minus 3.1 degrees at Ballyhaise, Co Cavan.
Four weather stations around the country had “ice days” which occur when temperatures stay about zero degrees for the whole day. “The last Ice day in Ireland was Dec 6th 2020 at Dunsany and before that it was at numerous stations on March 2nd, 2018 during Storm Emma,” Met Éireann said.
A status yellow low-temperature warning has been issued for the Republic until noon on Friday.
The forecaster said it would remain very cold through the week with widespread “sharp to severe frosts and icy stretches”, and some showers of hail, sleet and snow will occur, mainly near coasts.
This will lead to treacherous conditions on paths and roads, travel disruption, potential for burst water pipes and damage to engines.
Met Éireann also warned of increased risks to vulnerable members of the community and animal welfare issues.
In the North, UK Met Office weather warnings for ice and fog remain in place until 10am on Tuesday.
The Road Safety Authority warned road users of the dangers posed by freezing fog, combined with widespread severe frost causing a risk of icy roads.
