Met Eireann forecasts that there will be a big drop in temperatures from highs of 11C later this week.
New Year's Day will be dry with varying amounts of cloud and some bright or sunny spells.
There will be frost and icy patches in parts at first with some mist too and temperatures reaching 8C.
Wednesday night will be windy but dry for the most part with clear spells and increasing cloud later.
Temperatures will dip to as low as 4C with strong and blustery winds.
For Thursday, Met Eireann says: "After a dry start, rain will spread from the west to all areas during the morning and early afternoon.
"Rain will be heavy and persistent for a while but will become light and patchy again by evening.
"A mild day with maximum temperatures of 10 to 11 degrees. South to southwest winds will remain strong throughout the day.
The double temperatures will drop to a freezing 2C on Thursday night though with a touch of ground frost possible.
Also, there is two warnings in place by Met Eireann, a status yellow gale warning and a status yellow small craft warning.
The gale warning means: "South to Southwest winds will reach gale force this evening and tonight on coasts from Slyne Head to Erris Head to Malin Head. South to Southwest winds will also touch gale force tonight in the Irish Sea."
For the small craft warning they state: "South to Southwest winds will gradually increase to force 6 or more from the Atlantic during Wednesday on all Irish Sea coasts."
