Met Éireann has said that frost, ice and freezing fog will continue ahead of milder conditions later in the weekend.
The national forecaster said that there will be unsettled weather from Sunday (December 18) with some wet and windy conditions at times.
A Status Orange weather warning for low temperatures and ice is due to remain in place until midday today.
Along with severe frost and ice, patches of freezing fog will result in hazardous driving conditions in places.
Counties affected are: Carlow; Kildare; Kilkenny; Laois; Longford; Louth; Meath; Offaly; Westmeath; Cavan; Monaghan; Clare; Cork; Kerry; Limerick; Tipperary; Galway; Leitrim; and Roscommon.
A Status Yellow low temperature and ice warning for other areas is in place until midday.
Meanwhile, a nationwide Status Yellow ice warning will come into force from midday today and will remain in place until midday tomorrow.
The forecaster said that showers of freezing rain, sleet and snow are possible.
Met Éireann
Most areas will be dry this morning with some winter sunshine, showers in the northwest will extend southeastwards into Connacht and Ulster as the day progresses.
There will be moderate southwest winds and temperatures will range from 0° to 4°.
Tonight will bring a mixture of clear spells and scattered showers, some of which will be wintry.
Temperatures will fall to between 0° and -3° in light to moderate southwest winds.
It will be cold and mostly dry on Saturday apart from southern and western coasts where there could be some showers.
Highest temperatures will reach 1° to 4° in general but could be 5° to 8° in the south and west. The southwest winds will be light to moderate.
On Saturday night, rain will spread from the south, southeasterly winds will be fresh to strong, with lowest temperatures ranging from 0° to 4°.
Milder conditions will set in on Sunday with temperatures climbing to 8° in north Ulster and 12° to 13° further south.
It will be windy with rain and drizzle, which will be most persistent in the south and west.
Met Éireann said that it will be much milder on Sunday night compared to recent times with temperatures staying around 10° to 12° in fresh and gusty southerly breezes.
Monday will be mild and breezy with rain extending to all parts by the afternoon.
There will be sunny spells and scattered showers on Tuesday and southwest winds will be strong and gusty in top temperatures of 7° to 10°.
Further sunny spells and scattered showers are currently forecast for Wednesday when daytime temperatures will be 6° to 9°.