Met Eireann have said that New Years Eve is set to be cold, frosty and dry nationwide with lowest temperatures of plus 2 to -2 C.
Some ice may form on untreated surfaces.
Leinster will experience showers gradually dying out, becoming mostly dry with clear spells.
Winds will moderate through the night.
It will be cold with lowest temperatures of -1 to +1 Celsius with frost and icy patches on untreated surfaces.
On New Year's Day cloudy and windy weather is expected for Leinster.
It will be dry at first but rain in southern parts of the province in the late morning will spread to all parts of the province by late afternoon and early evening, the rain heavy at times.
Highest temperatures of 6 to 10 degrees.
Meanwhile Connaught is set for showers for a time tonight but they will gradually die out and it will become mostly dry with clear spells.
Winds will moderate through the night but stay fresh along the coast.
Lowest temperatures -1 to +1 degrees Celsius, resulting in frost and icy patches on untreated surfaces.
Western counties will experience a frosty start on New Year's Day with bright spells, however cloud will increase in the morning.
Outbreaks of rain and drizzle in the west and south of the province will become heavy and persistent.
In Munster showers will gradually die out and it will be mostly dry with clear spells.
Winds will moderate through the night and back south to southeast by dawn.
Lowest temperatures +2 to -1 degrees Celsius, resulting in ground frost and icy patches on untreated surfaces.
New Year's Day in Munster will be cloudy with rain becoming widespread and heavy spreading to all parts through the afternoon.
It will feel cold with highest temperatures 8 to 10 degrees Celsius in fresh to strong and gusty southeasterly winds.
Ulster is set to experience showers for a time early tonight but it will gradually become mostly dry with clear spells.
Frost&icy patches at first Shwrs/longer outbreaks of rain this morn some wintry on high ground,risk of isol thunderstorms Bec windy High5-9C— Met Éireann (@MetEireann) December 31, 2015
Scattered showers and longer outbreaks of rain. Some thunderstorms also. Becoming drier this evening. Windy and cold with highs of 4 to 9C— Met Éireann (@MetEireann) December 31, 2015
Lowest temperatures -2 to +2 degrees Celsius, resulting in ground frost and icy patches on untreated surfaces.
New Year's Day up north will get off to a frosty start with bright spells.
Outbreaks of rain and drizzle will develop in southern parts of the province in the afternoon and will spread to all parts in the evening.
Highest temperatures 6 to 8 degrees.
Meanwhile it has been confirmed that the country is on course for the wettest December on record.
As the clean-up following Storm Frank continues, Met Éireann today warned that two further bouts of heavy rain are due over the coming days.
Approximately 100 homes have been affected by the latest storm - compared to around 60 impacted as a result of Storm Desmond.
Forecaster Gerald Fleming said December has been the wettest month on record, which Cork receiving three times the normal rainfall.
Some 193mm fell in Dublin this month – compared to the average of 73mm.
And at Markree Castle in Sligo, 292mm of rainfall was recorded compared in December to the average level of 126mm.
“On almost all of our stations, it’s been the wettest December on record,” Mr Fleming said.
“I think it gives some context as to what we are living through, I suppose, in terms of the unusual nature of the weather,” he said.
In relation to the latest weather forecaster, Mr Fleming said that New Years Night will be dry, crisp and frosty.
But he said there is another weather system heading towards Ireland tomorrow and a further system on Sunday.
“So we have two more pelts of rain coming over the next few days,” Mr Fleming said, adding that the bad weather will mainly impact the south and south west.
The weather will remain unsettled and cold next week, however, Mr Fleming said it is too early to give any detailed forecast.
Meanwhile, the Office of Public Works (OPW) said all levels in the river Shannon catchment have risen over the last 48 hours.
Speaking to reporters following a meeting of the Emergency taskforce, the OPW’s Jim Casey said river levels at areas such as Athlone are of particular concern.
Many parts of the country remains on flood alert and pumping will have to take place for quite some time, Mr Casey added.
Chief Executive of Galway City Council Brendan McGrath said there are “slight improvements” in some areas but warned that roads remain treacherous.
He said he is “very concerned” about the Shannon in Athlone, which is now 5cm off its 2009 levels.
The HSE today warned people to be mindful about approaching floodwaters, while An Garda Síochána urged people to check in on their elderly neighbours if it is safe to do so.
Motorists have been urged to slow down when driving.
Meanwhile, the Defence Forces continued to dispatch personnel to flood-hit areas.