Met Éireann has forecast temperatures as low as -5 degrees in some areas tonight with snowshowers over Munster, east Leinster and parts of Ulster.
Tonight will be colder than last night and there will be widespread frost, forecaster Evelyn Blackburn said.
Bad weather led to further disruption for travellers today as snow and freezing temperatures spread across Europe.
Continuing snowfall and freezing temperatures caused further transport chaos in Britain and further afield. Earlier today parts of Kerry and Cork were experiencing problems due to snow and icy conditions.
Dublin City Council will have its gritters out on the roads overnight, with routes viewable here.
For evening commuters, AA Roadwatch has warned of icy conditions on the M1 from Drogheda north to Newry on the A1. There are also extremely icy patches near Kilkeel, Co Down.
Up to six inches of snow fell on the Dingle Peninsula overnight and AA Roadwatch has advised motorists to avoid the Conor Pass. It said there are slushy conditions around Tralee. Particular care is needed on the N86 Tralee/Dingle Road, N72 Tralee/Castlemaine Road at Quills Cross and the N21 Tralee/Limerick Road, especially between Castleisland and Abbeyfeale.
Heavy showers of sleet and snow fell in Cork in the early hours of this morning, causing traffic disruption in parts of the county.
Affected areas included Donoughmore, Mallow, Kildorrery, Whitechurch, Glenville, Carrignavar, Mitchelstown and Crookstown. Diversions were put in place around Rockchapel and Newmarket.
Snowfall was also reported in West Cork in Enniskeane, Bantry, Dunmanway and Bandon.
While driving conditions in most areas were improving this afternoon, care was advised in many parts of Louth, Meath, Monaghan, Wicklow and Cavan.
Age Action Ireland has called on the public to stay in contact with their older neighbours and for people to take steps to protect themselves and ensure they remain warm in their homes during the current cold spell. “Cold weather can kill and does kill in Ireland, making the winter a particularly challenging period for older people in particular” Age Action spokesman Eamon Timmins said. “Snow and ice make that challenge even greater as many older people may not be able to get out to buy food, fuel or medical supplies.”
With parts of Ireland experiencing snowfalls in recent days and more snow and icy conditions forecast for the coming days, Mr Timmins called for vigilance.
"If there is an older person living in your neighbourhood we would encourage you to call or phone them to check if they need anything," Mr Timmins said.
Met Éireann has said that outbreaks of rain, sleet and snow affecting southwestern areas will die out in Ireland this morning but will return by evening. Wintry showers will continue in the east and north, falling as snow on higher ground.
Aer Lingus has cancelled a dozen Irish flights between Dublin and Amsterdam, Frankfurt, Milan, Munich, Paris, London Heathrow and between Cork and Paris. Aer Lingus urged all customers travelling to check the status of their flights.
Ryanair has also cancelled some Irish flights. It said passengers on cancelled flights can transfer free of charge or receive a refund.
The operator of London's Heathrow airport said today's flight schedule would be cut by 10 per cent. That number could rise, depending on conditions at other European airports, Heathrow said. Ryanair flights to and from Stansted are also affected. Other UK airports including Gatwick and Birmingham also experienced disruption to flights because of the wintry conditions, while Robin Hood Airport near Doncaster, South Yorkshire, was closed, along with the runway at East Midlands Airport.
The Paris airport operator, ADP, said airlines have cancelled some 40 per cent of flights in and out of the two main airports on the outskirts of Paris, Charles de Gaulle and Orly, primarily reducing short-haul services. Travellers scheduled to travel today are advised to check the status of their flights prior to departing for the airport.
Bus Éireann has said services are operating as normal, with some short delays in Cork, Dublin, Cavan, Meath, Kerry and Limerick.
Meanwhile, the fourth person killed in an avalanche in the Scottish Highlands in which an Irish doctor died has been named by police in the UK.
Rachel Majumdar (29), a doctor working at Harrogate District Hospital in North Yorkshire, was originally from Merseyside and was most recently living in Leeds.
The avalanche struck at about 2pm on Saturday as a group of six friends made their descent from Bidean Nam Bian in Glencoe.
PhD students Christopher Bell (24), and Tom Chesters (28), and 25-year-old junior doctor Una Finnegan died as the slope they were walking on gave way as they made their way down the mountain.
Ms Finnegan's former schoolteacher said the young woman had wanted to make a difference with her life.
Nicola Madden, vice-principal of Dalriada School in Ballymoney, said the former pupil would be badly missed.
"She was bright, bubbly, talented, an amazing student, and academically she was brilliant - one of the top students," she said.
Ms Finnegan, who secured nine A*s and one A in her GCSEs in 2004, had been involved in the Duke of Edinburgh scheme of hillwalking for young people at the school, along with her twin sister, and that led to a love of the mountains and outdoors, Ms Madden added.
She was inspired to become a doctor after attending a humanitarian mission to Moldova in eastern Europe and meeting medics there, the senior teacher said.
"She just had a great zest for life and did actually want to make a difference," Ms Madden said.
Ms Finnegan's father Dr Owen Finnegan was a heart and chest consultant at the Causeway Hospital in Coleraine.
Ms Finnegan had studied medicine at Newcastle University and took her masters in anthropology of health and illness in Edinburgh, where she continued to live.
Independent Stormont MLA for the Coleraine area David McClarty, who knows the victim's father, said: "This is just such a tragedy to be visited upon this family."
A 24-year-old woman from the Durham area, who was seriously hurt in the incident, remains in a critical condition in hospital in Glasgow.
Additional reporting PA