Commuters and air travellers were facing further delays as the extreme weather threatened to wreak more havoc on the country's transport system.
Forecasters said heavy snow showers - as much as 12cm in some areas - were expected again in Munster, Connacht and Leinster along with severe frost, ice and fog.
Scattered snow was also predicted for north and west Ulster, Met Eireann cautioned in its latest severe weather warning.
Dublin Airport said it was fully operational after crews worked through the night to clear runways, but disruption could be expected if the weather deteriorates once more.
Passengers were advised to contact their airline or consult its website before travelling to the airport.
Bus Eireann warned of cancelled services between Dublin and Derry as well as Limerick and Galway, while delays would hit several other services.
While some delays were expected on the railways, Iarnrod Eireann said full services were continuing on Intercity, DART and Commuter routes.
Dublin Bus said the weather was causing diversions and curtailments on a number of services while slow traffic would impact further on journey times.
Temperatures plummeted as low as minus 14.4C in Ballyhaise in Co Cavan overnight.
The National Roads Authority (NRA) said it had 8,000 tonnes of salt left, with 2,000 tonnes used on average each day.