Numerous schools in the west and northwest have been forced to close for a second day running because of freezing conditions.
Motorists are being advised to give themselves plenty of time for journeys as the cold snap continues.
Met Éireann reported that temperatures fell well below zero in all parts of the country overnight.
Scattered hail, snow and severe frost are making road conditions dangerous in most areas particularly in Connacht, Ulster and west Munster.
Snow fell along the west and northern coasts, from Kerry through Galway and Mayo and across Donegal, with 5cm of snow recorded at Knock Airport.
The lowest recorded overnight temperature was in Birr in Co Offaly with a reading of minus five.
