Met Eireann are predicting a freezing winter turn as temperatures are set to plummet to -3C this week.
It will be cold tonight with frost developing in places and lows of -2C expected in Connacht and Munster.
And Friday will be the coldest night of the week with temperatures falling as low as -3C in places.
A Met Eireann forecaster said: "Frost and mist patches will clear during the morning to leave a cold and bright day with sunny spells however scattered showers will increase over Connacht and Ulster during the afternoon and evening. Highest temperatures of 6 to 9 degrees in moderate west or northwest breezes.
"Becoming mostly dry tonight with just isolated showers in the west, otherwise a mix of cloud and good clear spells. Mist and fog will form towards morning in a light westerly breeze. Frost developing with lowest temperatures of -2 to +3 degrees, coolest in the Connacht and Munster.
"Thursday will be mostly dry and cool with fog lingering in some parts through much of the day, however occasional sunny spells may develop during the afternoon. Cool with highest temperatures of 4 to 8 degrees in light variable breezes.
"Another mainly dry but cold and frosty night. Dense fog will develop in places in near calm conditions. Lowest temperatures generally of -2 to +3 degrees.
"A cold day on Friday with frost and fog lingering in the morning. However, it will remain largely dry apart from showers in the northwest, with sunny spells developing through the day. Temperatures generally reaching just 3 to 6 degrees with light easterly or variable breezes.
"Continuing cold on Friday night with lowest temperatures of -3 to +1 degrees. Mainly dry with clear spells but isolated showers will develop overnight."
As we head into the weekend it will stay largely cool with "further frosts" expected on Sunday and into next week.
A forecaster added: "A mix of sunny spells and scattered showers. A cold start to the day will give way to slightly milder conditions from the south with highest temperatures of 7 to 11 degrees in a light easterly breeze.
"Current indications are that it will remain slightly colder than normal for Sunday and into next week with some further frosts possible. Continuing largely dry also with scattered showers."
