Motorists are being warned to take extra care on the roads as temperatures are forecast to plummet to –4C overnight.
Brian Farrell of the Road Safety Authority says drivers should slow down as icy conditions are forecast.
Snowfalls in England have led to flight delays at Heathrow and Gatwick.
126 flights were cancelled at Heathrow's Terminal 5 . Of these cancellations, 114 were due to snow and the remaining 12 were down to BAA's technical fault.
Snow had also led to the cancellation of 32 BA flights at Gatwick Airport. Road access to the airport has also been hampered by snow.
Ferry sailings have also been disrupted by the weather.
This morning's Irish Ferries Jonathon Swift sailing from Dublin to Holyhead and today’s 2.30pm sailing were cancelled.
All other Irish Ferries sailings and all Stena Line services are operating normally.
The wintry conditions, which included snowfalls in parts of the country early today, have also caused the cancellation of the Co Roscommon ploughing championships in Kiltoom.
The event, which attracts up to 5,000 people, was due to take place on a farm near Athlone. Based on today's forecast, the organising committee decided yesterday to defer the event until 27 April.
Met Éireann says the wintry weather will continue for the next couple of days.
There were frost and icy stretches in places this morning and drivers were being advised to drive with care.
Some heavy snowfalls are expected, especially across the northern half of the country, along with a risk of thunder.
Age Action has urged members of the general public to be good neighbours by keeping an eye out for their older relatives, friends and neighbours during the current freezing weather.
'We would encourage people to drop in to ensure their older neighbour is okay and has sufficient food and fuel,' Age Action spokesman Eamon Timmins said.