Milder temperatures are due to return later on today and tomorrow.
Highs of 10C are forecast for Monday, after last night's lows of -3C.
Frost clearing in E.Fog staying for a time in Mid.Else dry/bright for day.Cloud increasing.Max 6-10.Tonite some
mist/dz Mainly dry.Min2-5— Met Éireann (@MetEireann) January 4, 2015
Drivers are being warned to take care on the roads this morning, as frost and ice are still clearing in places.
Frost & fog in many areas this morning - clear your windscreen & mirrors before you set out Reduce speed & take care! pic.twitter.com/ttWzUz07CY— An Garda Síochána (@GardaTraffic) January 4, 2015
Forecaster with Met Éireann John Eagleton said that Ireland has enjoyed mainly mild temperatures this winter.
"Generally the whole trend has been for mild weather this season so far, but there have been brief interludes of colder weather, and really that's not surprising - it is the middle of winter," he said.
"So sometimes we get rain going through and then we get colder air behind it, but it's then pushed aside by southerly winds coming up, bringing that milder air up from the south.
"Overall, it's been a mild winter."
It’s not all good news however, as Eagleton warned of some mixed weather on the way next week.
“It looks like we’ll have a band of rain there on Tuesday, and another one after midweek as well,” he said.
“There’ll be a brief cold period then on Thursday as the winds go northerly, that typically happens when a cold front goes through, we get colder air behind it.
“Sometimes that persists for several days, but what’s happening this season is that it’s being moved aside by more milder air coming up from the south.”