A status yellow low temperature warning has been issued for Monday night and Tuesday morning
Cold weather here & in the UK has led to school closures, flight cancellations and treacherous roads in various parts of the country.
Temperatures in the middle of the country, around Tipperary, were expected to fall as low as minus 8 degrees this morning.
Forecasters say there are sub-freezing conditions in most parts of the country, with temperatures only expected to reach between 3 and 5 degrees during the day.
A status orange low temperature warning was in place for the country overnight and into this morning.
This afternoon, Met Éireann has issued a lower-level status yellow for the country. It is valid between 8pm tonight and 10am tomorrow morning.
Today, number of schools in counties such as Longford and Galway have been closed for the day.
Five flights to London Heathrow from Dublin have also been cancelled as a knock-on effect of the 'big freeze' that hit the UK over the weekend.
Shannon Airport has also reported "some minimal disruption to today's flight schedule" due to weather conditions in the UK.
John Eagleton, forecaster with Met Éireann, told Newstalk Breakfast: "There's been a severe frost last night.
"The worst is over, as temperatures were lowest yesterday and last night. Through the rest of the week, [temperatures] are going to remain low - but they won't be as low as they were."
The AA's Gemma Ryan says Galway, Roscommon, Sligo, Donegal and Cavan appear to be the counties worst affected by ice, with widespread frost elsewhere.
She urged drivers to use dip headlights while driving in such conditions, and reminded motorists that stopping distances are up to ten times longer in ice and snow.