A Status Yellow snow and ice warning will remain in place around the country until Saturday afternoon.
Met Éireann said it will stay very cold for the remainder of the week with widespread frost, ice and lying snow in places.
Significant accumulations of snow are possible on high ground, with some accumulations to lower ground at times.
TODAY
It will be bitterly cold and rather windy today.
Rain in the west and southwest will gradually move up into other areas, turning heavy and persistent, especially in southern counties.
The rain will also turn to sleet and snow for a time over parts of Connacht, Leinster and inland Munster.
Whilst snow accumulations will mainly occur on higher ground, some lower levels will see moderate accumulations.
Highest temperatures of 2C to 7C with an added wind chill factor - owing to a fresh to strong and gusty east to southeast wind.
TONIGHT
Extremely cold this evening and overnight with brisk northeasterlies and further wintry falls.
There will be some snow accumulations on lower ground, mainly in the south and east
There will be some frost and ice, resulting in treacherous conditions.
Lowest temperatures of 0C to -6C, coldest across Ulster and west Connacht.