Motorists are being urged to drive with caution as icy conditions are again making driving dangerous in some areas.
The worst affected parts of the country are counties Meath, Westmeath, Laois, Offaly, Tipperary and Kilkenny and west Clare.
Black ice has been reported on several secondary routes in Leinster and Munster.
Gardaí say it is very icy on the M4 near Leixlip, Co Kildare and there have been a number of minor collisions in the area.
The N6 between Ballinasloe and Galway, the road between Ennis and Gort and the N17 between Tuam and Galway are dangerous along certain sections.
AA Roadwatch has reminded motorists to use gentle manoeuvres on icy roads.
Met Éireann has said that the frost and ice patches should clear later today and most places will be dry with sunny spells.
It will be cold again tonight but temperatures will not drop as low as during the cold snap in December.
