An Status Orange warning is in place with temperatures set to plunge significantly on Wednesday night, through to Thursday.
The low temperature/ice warning is in place for Carlow, Kildare, Kilkenny, Laois, Longford, Louth, Meath, Offaly, Westmeath, Cavan, Monaghan, Clare, Cork, Kerry, Limerick, Tipperary, Galway, Leitrim and Roscommon.
Met Éireann Weather Warning
The national forecaster has warned that it will be extremely cold on Wednesday night with widespread temperatures below -5 degrees leading to severe frost and ice
This will lead to "treacherous conditions on paths and roads," Met Éireann said.
Met Éireann has also issued another Status Orange alert from 6pm tomorrow until 12pm on Friday for Leinster, Connacht, Munster and Cavan and Monaghan, with lows of -5C forecast, leading to severe frost and ice.
"Remaining very cold through the week with widespread sharp to severe frosts and icy stretches," Met Éireann outlined.
It predicted that some showers of hail, sleet and snow will occur, mainly near coasts. Accumulations at lower levels are expected to remain low.
Speaking on RTÉ's Morning Ireland earlier on Wednesday, meteorologist Joanna Donnelly forecast a low temperature of -7C nationally, with temperatures possibly dropping to -11C in places.
"I have the -7 widely in the forecast for overnight tonight, but it's going to be much colder than that in isolated areas, there's -11 showing up on my charts here," Ms Donnelly said.
Overnight temperatures went down to -7.5 at the Mount Dillon weather station in Co Longford, she said. However, temperatures were generally down to -4C or -5C last night overall.
Met Éireann warned that there is a potential for burst water pipes and damage to engines.
The national forecaster also reminded people of increased risks to vulnerable members of the community at this time.
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