Met Éireann has issued a status yellow snow-ice for several counties.
The alert is in place for Dublin, Connacht, Cavan, Monaghan, Donegal, Louth and Wicklow.
The forecaster is warning of ice in parts tonight with wintry outbreaks.
Some snow accumulations are also possible before Thursday morning, mainly across the north and on higher ground elsewhere.
The yellow alert is in effect from 8.00pm Wednesday until 10.00am Thursday.
An earlier nationwide yellow warning for snow and ice has been stood down.
— Met Éireann (@MetEireann) February 12, 2020
Rain is set to extend countrywide tonight, turning wintry across Connacht and Ulster.
This is forecast to fall as snow over high ground with sleet at lower levels.
Becoming rather windy then too, as southerly winds increase fresh to strong, with gales developing on some southern coasts.
It will remain wintry across Ulster until Thursday morning with frost and ice in parts.
Lowest temperatures of -1 to +4° are forecast - coldest across the north and northwest.
Thursday morning will see some lying snow across Ulster, with further wintry falls here for a time.
There will be scattered rain showers and sunny spells elsewhere, but overall a lot of dry weather in moderate to fresh northwest breezes.
Highest temperatures will range from 4 to 6° in Ulster to 9 or 10° in the south.