The lowest temperatures were recorded at Eireen Weather Observatory in Mullingar, County Westmeath, in central Ireland, with -7C recorded in Athenry, County Galway, and -6.7C recorded in Oak Park, County Carlow.
Power restoration efforts are still ongoing, with around 200 homes, farms and businesses said to be affected, with around 4,500 customers without water, mainly in Counties Tipperary, Limerick and Kerry. .
An orange weather warning for low temperatures and ice was in place for Leinster, Cavan, Monaghan, Munster and Connacht until 11am on Thursday.
On Thursday morning, low temperatures and Another orange weather warning for ice has been issued.
Transport disruptions, delays and poor visibility are expected in areas affected by this alert, which applies from 7pm on Thursday to 8am on Friday.
A yellow warning for low temperatures and ice is in place across Ireland until midday on Friday, with widespread frost, ice and snow expected to form, with freezing fog expected to develop in some parts. There is also the possibility of movement confusion and poor visibility.
Meanwhile, Northern Ireland is under a yellow ice warning for the entire region until 10am on Friday.
It comes after previous warnings for snow, ice and freezing fog were lifted on Thursday morning after a night when a low of -7C was recorded in Castlederg, Co Tyrone.
Police on Thursday urged motorists to slow down in icy conditions and fog and to maintain a safe distance from vehicles in front of them.
The situation has caused some transportation disruptions and some schools have been closed.