A status yellow low temperature and ice warning has been issued for the entire country.
It will begin at 6pm on Thursday evening and remain in place until 11am on Friday morning.
Met Éireann is warning of widespread frost and ice, as temperatures fall to minus 3 degrees or lower in many places overnight, while they could fall as low as -5 degrees.
The national forecaster warned that the conditions will bring hazardous driving conditions and "animal welfare issues".
The forecast for Thursday night reads: "Cold tonight with clear spells and while it'll be dry in most areas, there'll be well scattered showers, mainly in the north and west, some wintry. Lowest temperatures of -5 to 0 degrees with widespread frost and some ice developing. Some fog and freezing fog will form too. Winds will be mostly light west to northwesterly or variable, but will be fresher in northern coastal parts."
On Friday morning, fog and frost are forecast. However, the weather will then clear with tempatures of 2 to 6 degrees.
The weekend will be “very cold”, according to the forecaster, with “some very disruptive and impactful weather likely”. An area of low pressure will dominate the weather, bringing heavy rain, sleet and “some disruptive amounts of snow”.
Temperatures will drop to -3 degrees on Friday night, dropping further to -5 degrees on Sunday night. The cold snap will extend into next week, with lows of -10 degrees expected on Tuesday night.
It will be bitterly cold on Wednesday with freezing fog, lying snow and icy conditions. Mainly dry, with just well scattered showers in the north and northwest. Daytime temperatures could be as low as -5 to +2 degrees.
Met Éireann meteorologist Liz Coleman said: “It’s going to feel much colder than it has recently, with daytime temperatures in the low single figures and night-time temperatures falling below zero in most areas.
“Widespread frost is expected with some ice, although generally dry conditions will limit ice formation to mainly areas of standing water or run-off. Nevertheless, do take care while out and about.
“While it will be cold, it will be mainly dry with sunny spells as the high pressure will prevent any significant rainfall."
In counties Antrim, Armagh, Down, Fermanagh, Tyrone and Derry, there is a yellow ice warning in place from the UK Met Office. This warning came into effect on Wednesday, and expires at 10am on Thursday morning.
