Two weather alerts have been issued by Met Éireann, as temperatures are set to drop back.
A status yellow snow and ice warning is in place for the entire country from 5.00am on Friday.
The forecaster says there will be scattered snow showers likely, most frequent in Ulster and Connacht.
While a yellow low temperature warning has also been issued.
Temperatures are set to be drop back to as low as -3C or -4C in places overnight and into Friday morning.
The forecaster says it will be "very cold" on Thursday night, with lowest air temperatures of 0 to -3C.
And it says Friday will be a cold, breezy day with some bright or sunny spells - but there will be showers of hail, sleet and snow in many areas with a slight risk of thundery bursts too.
It comes as motorists are urged to take extra caution on the roads, amid alerts for black ice and sun glare.
The Road Safety Authority (RSA) is advising all road users to take extra care as frosty and ‘blinding’ sun conditions are forecast.
Cold wintry weather will develop too mainly in the north and west of the county from Thursday and into the weekend.
The RSA says lower temperatures will mean roads may be icy with risk of black ice.
It is asking road users to check local weather and traffic conditions, and be aware of the conditions before setting out on a trip.
It has issued the following advice for road users:
- Clear your windows and mirrors before you set out, carry a screen scraper and de-icer. Do not use hot water on the windscreen as it can crack the glass
- Watch out for black ice. If the road looks polished or glossy it could be, black ice which is difficult to see
The RSA says black ice is nearly transparent ice and often looks like a harmless puddle or is overlooked entirely
It can occur especially in sheltered or shaded areas on roads, under trees and adjacent to high walls
- Use dipped headlights at all times of poor visibility to ensure you are seen by other motorists
- Watch out for vulnerable road users such as pedestrians, cyclists and motorcyclists and allow extra space