Met Eireann has warned of frost and ice as the mercury is set to plummet to subzero temperatures.
But there is some good news as the national forecaster said high pressure will bring long sunny spells and dry weather by the end of the week.
Today will start off largely dry with scattered showers and sunny spells. But further outbreaks of rain will spread across Munster and Leinster from the south later in the morning.
The rain will ease into the Irish Sea with the afternoon bringing sunny spells and isolated showers from the west.
It will be a mild day with temperatures reaching as high as 10 degrees.
But the mercury is set to plunge tonight with temperatures reaching the lows of -2 degrees with frost and icy patches developing.
Tomorrow will see a cold and frosty start but any frost and ice will clear to leave a dry and bright day with long sunny spells.
But the northern half of the country will be covered with patchy cloud in the afternoon.
Temperatures will range between 7 and 9 degrees.
Here is the forecast for the rest of the week:
Tomorrow night
A Met Eireann forecaster said: "Another cold and generally dry night with long clear spells, though it will turn cloudier overnight with isolated patches of drizzle in the east and south.
"Lowest temperatures of -2 to +2 degrees, with frost and ice patches developing in a light easterly breeze.
Wednesday
"Generally cloudy on Wednesday with scattered patches of light rain and drizzle spreading from the south.
"More persistent rain will move into western and southwestern coastal counties in the evening. Highest temperatures of 8 to 10 degrees in light to moderate southeasterly winds.
Wednesday night
"Rain will spread northeastwards across the country on Wednesday night. Clear spells and scattered showers will follow into Connacht and Munster as the rain clears overnight. Lowest temperatures of 2 to 5 degrees in light winds.
Thursday
"Rain will gradually clear from the east and north through the morning and afternoon, leaving a mix of sunny spells and scattered showers, most frequent and prolonged over the western half of the country. Highest temperatures of 7 to 10 degrees in light to moderate northwesterly winds.
Thursday night
"A cold and generally dry night with long clear spells and just isolated showers, mainly near western and northern coasts. Lowest temperatures of -1 to +2 degrees in light westerly winds.
Friday
"Another bright day with sunny spells and scattered light showers. Highest temperatures of 6 to 9 degrees in a light breeze."
Weekend
"High pressure will build across the country over the weekend, bringing plenty of dry and bright weather with long sunny spells. However, current indications suggest that another spell of rain will cross the country later Sunday."
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