The cold snap will continue until at least Thursday with low temperatures and wintry showers throughout the day on Wednesday, Met Éireann has said.
Tuesday saw temperatures drop to as low as minus seven degrees in parts of the midlands, with two yellow weather warnings in place for half the country.
A status yellow snow and ice warning is in place for counties Donegal, Leitrim and Sligo until 9am on Wednesday.
A status yellow snow and ice warning was also issued for counties Cavan, Monaghan, Cork, Kerry, Longford, Louth, Meath, Offaly, Westmeath, Mayo and Roscommon. The warning is in place from 5.30pm on Tuesday to 9am on Wednesday.
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Met Éireann has also warned frost and ice may lead to “hazardous travelling conditions”, with snow reported in parts of Kerry, west Cork and in the northwest.
A number of schools in Co Donegal took the decision to close on Tuesday, as well as some schools in Co Cork, due to the weather conditions.
In Northern Ireland a weather warning for snow and ice across all six counties is also in effect until noon on Wednesday, with motorists advised there may be disruptions to roads.
[ Drivers warned to be ‘extra cautious’ as status yellow ice alert issuedOpens in new window ]
Wednesday’s temperatures are forecast to remain cold, although it will be warmer than Tuesday.
The national forecaster said there will be wintry showers in the northwest and southwest of the country, with snow accumulations possible, especially in mountainous areas.
On the possibility for continued school closures in counties experiencing significant snowfall, a spokesman for the Department of Education said there is no onus on schools to alert them to closures, adding that it is at the discretion of the school principal and/or the board of management.
Wednesday will see a similar mix of sunny spells and wintry showers, with temperatures staying below seven degrees, and dropping to as low as minus three during a frosty night.
Tuesday night was cold, with scattered wintry showers, mainly affecting Atlantic coastal counties.
The national forecaster said the weather may turn slightly warmer on Friday, when highest temperatures will range from five to nine degrees.
Temperatures will drop again once it gets dark, which means that some of those showers may fall increasingly as sleet or snow in places, especially over the northern half of the country.
Met Éireann said the cold spell will last until late on Thursday and into Friday.
The current cold snap is due to the return of colder Arctic air, the national forecaster said, and while it’s not as cold as the wintry conditions before Christmas, there is more moisture at present, which will mean more sleet and snow showers, especially in the west and north.