Temperatures are set to drop to -8 degrees on Friday night as a yellow level weather warning remains in place across the country.
A low temperature and ice warning is in place until 11am on Friday with Met Éireann warning of widespread frost and ice this morning.
The UK Met Office has also issued a yellow ice warning across Northern Ireland until midday on Friday.
AA Roadwatch has said particular care is needed on secondary and minor roads due to widespread icy conditions.
Overall it will be dry with bright winter sunshine on Friday with some scattered wintry showers likely in Ulster and east Leinster.
Highest temperatures will be between 1 and 5 degrees, in mostly light to moderate northerly breezes.
Friday night will be extremely cold with widespread frost and ice. It will be dry, calm and clear in many areas, however some wintry showers will affect the east of Leinster.
Temperatures will plummet to between -2 and -8 degrees, with fog forming in some areas.
Saturday
Met Éireann has warned it will be extremely frosty and icy on Saturday morning with freezing fog in parts too. Some wintry showers will affect the east of Leinster, with patchy rain and drizzle gradually moving into the west and northwest.
Other areas will stay dry with some sunny spells with highest temperatures between 0 to 4 degrees.
Patchy drizzle will affect parts of the north and west on Saturday night, but otherwise it will be dry. Lowest temperatures will be between -3 to 2 degrees, with possible frost and ice setting in. There will be some mist and fog patches too, in just light westerly breezes.
Sunday
Many areas will be dry with a mix of cloud and some sunny spells, and just light southwesterly breezes on Sunday. However, patchy drizzle will continue to affect northern and western counties.
Highest temperatures will be between 5 to 8 degrees with further patchy drizzle across the west and north overnight. Some frost is possible with lowest temperatures between 1 to 5 degrees in moderate southwest breezes.
Monday
Monday will be cloudy and breezy with outbreaks of rain and drizzle. Highest temperatures will be between 7 and 10 degrees, in fresh and gusty southwesterly winds.
Scattered outbreaks of rain will persist overnight, turning heavy in places later. Lowest temperatures of between 4 to 7 degrees in fresh southwest winds.
