A national weather warning for widespread "severe" frost on Thursday which will create icy conditions on roads has been issued by Met Éireann.
Snowfall up to 2cm deep was forecast for 18 counties, including Dublin, Cork, Louth, Wicklow and Limerick, according to a second status yellow weather warning issued on Thursday afternoon.
The counties covered by the snow weather warning are: Dublin, Donegal, Cavan, Monaghan, Carlow, Kildare, Kilkenny, Laois, Longford, Louth, Wicklow, Offaly, Westmeath, Meath, Leitrim, Cork, Limerick and Tipperary.
The forecast snow will likely be cleared by rain on Friday morning in most places.
Icy conditions were set to develop again, particularly across Leinster and Ulster, on Thursday evening and overnight, according to Met Éireann.
The weather on Thursday in most areas was cold, with values struggling to make 5 degrees. Showers of sleet and snow were forecast to sweep across the country from the west and southwest, with large accumulations possible on higher ground.
Climbers and hikers were advised to exercise caution as winds and low temperatures make mountain conditions hazardous.
In the southwest, deep snow was on all but the lower levels on the MacGillycuddy’s Reeks, according to kerryclimbing.ie, which said the Devil’s Ladder, one of the most difficult ascents, was “extremely treacherous”.
Black Ice
Temperatures were forecast to dip as low as -4 degrees, meaning roads and paths may be icy, and as a result people are warned to be aware of black ice.
Racing in Leopardstown and Limerick went ahead on Thursday, after both courses passed inspections in the morning.
The initial outlook for Friday is for a brighter day with scattered rain and hail showers, according to Met Éireann. Average temperatures will be between 5 to 9 degrees, but there may be heavy rain in the southwest of the country.
The weekend will be mixed, with slightly higher temperatures, patches of heavy rain and strong winds, some sunny spells and frost.
UK
Plunging temperatures and widespread ice are expected to cause more problems for road and air travellers in the UK. The UK Met Office has issued yellow warnings of ice for large parts of England, Wales, Scotland and Northern Ireland after snow brought major disruption and power cuts to swathes of the UK on Wednesday.
There were reports of passengers being left “stranded” at Stansted Airport on Wednesday evening after hundreds were left waiting to rebook tickets on dozens of flights which were cancelled due to earlier bad weather.
Airport officials were on standby with beds and blankets for anyone who was unable to get home or find accommodation as they attempted to clear the backlog.
However, flights departing from Dublin, Shannon and Cork Airports to the UK on Thursday were operating on schedule as normal, without any reported delays to date.
Sub-zero temperatures were expected widely across the UK again on Thursday night, with the mercury expected to plunge as low as -12 degrees in parts of Scotland and Wales.
–Additional reporting PA
