Icy stretches and patches of freezing fog are making driving conditions difficult for motorists.
Temperatures plunged to as low as minus 2 degrees Celsius overnight.
A Met Eireann cold weather alert is in effect until midday.
It's a yellow low temperature and ice warning.
Alan O'Reilly, from Carlow Weather, says conditions are treacherous in places.
"Very cold temperatures this morning, with widespread frost and icy patches, and also some patches of freezing fog this morning, making for some locally treacherous conditions.
"There'll also be some wintery showers."
