A new Status Orange warning for Freezing Fog is coming into effect this afternoon for 21 counties.
The areas affected include Connacht, Carlow, Dublin, Kildare, Kilkenny, Laois, Longford, Louth, Meath, Offaly, Westmeath, Cavan, Donegal, Monaghan, Clare, Limerick, Tipperary.
It's in force from midday today until midnight.
Met Éireann is expecting freezing fog that is "dense in places" through the afternoon into the night.
It's also warned of "very hazardous" driving conditions.
Frosty The Snowman
Cathal Nolan from Ireland's Weather Channel says this cold snap could fall away into the weekend.
But Cathal says, for now, it's staying absolutely bitterly cold.
"With that, temperatures by day really struggling to in many parts of the country to break freezing, with that freezing fog."
He says "severe" temperatures overnight will get down as low at -7 or -8 degrees in some areas.
⚠️Status Orange Freezing Fog Warning issued⚠️
Valid: Midday to midnight Monday
Affected Regions: Connacht, Carlow, Cavan, Clare, Donegal, Dublin, Kildare, Kilkenny, Laois, Limerick, Longford, Louth, Mayo, Meath, Monaghan, Offaly, Tipperary & Westmeathhttps://t.co/ZsjQsKCXDy pic.twitter.com/FITVVpoPV9— Met Éireann (@MetEireann) December 12, 2022
Schools
Meanwhile, schools will get to make their own decisions - if they should stay open or not as the cold weather continues.
Principals say the National Emergency Co-ordination Group, which met yesterday, has left it to them to decide.
Paul Crone from the National Association of Principals and Deputy Principals explains:
Paul says under and orange or a yellow warning, schools "will do their own risk assessment."
That includes looking at things like heating, access, health and safety.
"They will be able to make decisions locally in relation to their own school," Paul says.