Temperatures are set to plummet with lows of 1C expected tonight - but it's not all bad news.
Weather experts warned of some "dense fog" in many parts of the country this morning, which will turn to rain across the west later.
But there is some good news, as conditions will remain mild for the time of year during the day with highs of 12C.
However it will turn much colder overnight, with lows of close to freezing expected.
A Met Eireann forecaster said: "Dense fog in many areas this morning, especially in Leinster and Ulster. Some patchy rain in Munster. Today will be mainly dry in Ulster and Leinster.
"Scattered outbreaks of rain in Munster and Connacht will spread northeastwards in the late afternoon and evening. Highest temperatures of 10 to 12 degrees with mostly light breezes.
"Tonight will be mostly cloudy with outbreaks of rain at times in most areas. Lowest temperatures of 1 to 5 degrees."
And a mixed week is in store from Monday onwards with some dry and bright spells along with some wetter conditions.
A forecaster added: "Monday will be mostly cloudy with scattered outbreaks of rain through the day. Highest temperatures of 9 to 11 degrees with mostly moderate northerly winds, fresher near north and west coasts.
"Tuesday will be largely dry and bright with sunny spells. Highest temperatures of 10 to 12 degrees with moderate northerly breezes.
"Wednesday will start off mainly dry with some sunny spells over the eastern half of the country. It will be cloudier further west with rain developing and then spreading eastwards across the country.
"The rain will clear on Wednesday night and showers will develop in the west later in the night. Highest temperatures of 7 to 9 degrees with moderate southerly breezes. The night will be cold with frost in places, especially in the east."
And while Friday will remain relatively dry it will again be cold and frosty overnight, with some "unsettled" weather and plenty of showers expected next weekend.
