The intense cold snap is going to continue until at least the end of next week.
Met Eireann is warning that freezing conditions will continue every night.
Many roads are dangerous again today with icy stretches, surface water and fallen debris following stromy conditions in parts of the country.
Jean Byrne from Met Eireann said there will be no letup for quite a while.
"The winds are going to be pretty slack at night and we are going to have clearer skies as well," she said.
"Temperatures are going to plummet each night. Tonight we are expecting -8 or -9, but from tomorrow night onwards they could fall even below that.
"We could see at times -12 or -13, or even slightly lower than that, any time between now and the end of next week."