Sub-zero conditions are expected later this week as temperatures are set to plummet to -3C.
And a wet and miserable week will continue as even more heavy rain is set to lash parts of the country later today.
However there is some good news, as some places will escape the worst of the showers, with sunshine even possible at times.
A Met Eireann forecaster said: "There will be a lot of dry weather today, but some scattered showers will occur, especially in the east where there could be some heavy bursts.
"Generally cloudy but some bright or sunny spells will break through. Highest temperatures 8 to 10 degrees in light to moderate northerly winds.
"Cloudy and mainly dry for much of the country tonight with just the odd shower. Winds will be light allowing some mist and fog patches to form. Lowest temperatures 2 to 6 degrees with grass frost possible in any clear spells."
And Thursday will swing from one extreme to another, with a relatively mild afternoon followed by a freezing cold and frosty night.
A forecaster added: "Thursday is looking largely dry and bright with some sunshine breaking through. Highest temperatures of 7 to 10 degrees. Winds will be light or moderate northerly.
"Turning cold on Thursday night, especially in the north and east where temperatures will drop back to between -3 and 0 degrees under clear skies, leading to frosty conditions.
"It will be less cold in the south with temperatures generally above freezing."
And there is more positive news as we look ahead to the weekend, with Saturday and Sunday expected to be dry and sunny in most of the country.
However experts warned that some rain will affect southern counties on Saturday, and it will be chilly overnight with temperatures close to freezing across Ireland.
