Two separate weather warnings for snow and low temperatures have been issued for the entire country.
Temperatures this evening can be expected to plummet to -3C and -4C.
According to the Met Éireann, snow and ice will lead to hazardous conditions.
Meteorologist Siobhán Ryan says conditions will be very dangerous for people out walking or driving tomorrow.
She said: "A very cold night ahead obviously. Again it's going to be very frosty and icy... particularly later tonight and first thing tomorrow."
"We're looking at a band of precipitation that's going to continue to sink down from the north-west of Ireland, and embedded in that will be some sleet and snow so actually some snow accumulations are possible before the night's end.
"We're looking at some treacherous conditions out there first thing tomorrow."
Tonight, a widespread frost is expected to set in early with icy stretches and some freezing fog.
Rain, sleet and snow will move down from the northwest with snow accumulations in some areas.
Lowest temperatures of -4C with the coldest expected across Leinster.
On Thursday morning, there will be snow accumulations to begin the day, but brighter conditions will extend across the country.
Met Éireann predicts another "raw day" with highs of just 1C to 5C.
The warning comes into effect from 11pm tonight until 11am tomorrow.
A low-temperature warning will also come into effect at 8pm and last until 10am on Thursday morning.