Freezing temperatures are expected to last until around midday.
There is currently a cold weather and ice warning in place for all parts of the country.
Last night, temperatures plummeted to -5C in some areas.
According to Transport Infrastructure Ireland, air temperatures on the Waterford bypass remained at -3C at 9.20 am this morning while it was -2.3C on the N25 in Dungarvan. Road temperatures were up to a degree colder.
Met Éireann forecaster Joanna Donnelly says it will stay that way for some time this morning.
"They'll continue right through until near midday with low, freezing temperatures and it is colder on the roads than that too so a cold start to the day," she said.
"The sun will start to clear and ice or frost around midday and then a small rise through the afternoon to about 4-7C."
