Snow, wind and rain weather warnings have been issued for various parts of the country this morning.
Temperatures are expected to drop further this evening with a national low temperature warning in effect from 8pm.
The warning is set to remain in place until Monday morning.
Met Éireann has said there will be "extremely low temperatures tonight with severe frost, ice and lying snow."
The evening will see lowest temperatures of -2C to -8C degrees. It will be coldest in east Connacht, Leinster and Ulster.
The forecaster has warned that the snow will lead to slippery paths and treacherous roads.
Snow has already been falling in many areas of the country.
A total of 11 counties - including Galway, Wicklow, Kilkenny and Tipperary - are currently under a Status Orange snow and ice warning.
Snow in Glencullen, Dublin 18, 10-12-2017. Image: Gaye O’Brien
The forecaster has also issued yellow wind and rain warnings across various counties.
Meanwhile, Cork City Council has issued an Orange Weather Warning:
“Westerly gales or strong gales continuing this morning on Irish coastal waters from Carnsore Point to Mizen Head to Loop Head and reaching storm force 10 for a time,” the council said in a statement.
Met Éireann forecaster Liz Walsh has said there is a big variance in temperatures across the country this morning:
“There is a front lying across the country and that front is slowly starting to sink southwards.
“There is rain, snow and sleet in that front.
“And as that front sinks southwards, it is going to draw the cold air behind it down with it.
“We can expect as we go through this afternoon, places that are at 6C or 7C degrees right now will actually decrease in temperatures.”
Meanwhile, Gardaí have issued a road safety notice for people living in counties affected by the orange weather warning.
The public is being warned against unnecessary travel in the affected areas.
With plenty of snow expected around the country today, Gardaí are urging the public to heed the changing conditions before travelling.
Drivers are being reminded that it takes longer to stop a vehicle on an icy road. Gardaí are urging people to slow down and to keep a safe distance from the car in front.
Motorists are also being advised to ensure that all ice is cleared from windscreens, windows and mirrors of vehicles before taking to the road - and are being warned to use hot water.
Gardaí also say that any snow must be cleared from the roof of the car, as it can fall onto the windscreen while braking, potentially causing restricted vision.
Assistant Commissioner Michael Finn is also urging motorcyclists and cyclists to not compromise their safety by the 'need' to travel in snowy or icy conditions.