Subzero temperatures will be recorded over two nights this bank holiday weekend.
Met Eireann is predicting "frosty and icy" nights as temperatures are to plunge to -2C in some parts of Ireland.
The national forecaster said there is a possibility of wintry showers affecting hilly areas on Saturday.
While it is to be a mainly sunny day, it will be breezy with highs of just 10C.
A spokeswoman said: "Early rain in the east and southeast soon clearing. Otherwise a bright, breezy and fairly sunny day.
"Some showers developing, these mainly in the north and west of the country, with an isolated hail shower possible, and perhaps wintry over hills.
"Top temperatures of 7C to 10C. Moderate to fresh west to northwest winds will be strong along west and northwest coasts."
Parts of the country will be as cold as -1C on Saturday night, with frost becoming widespread in the southern half of Ireland.
The spokeswoman added: "It will be cold overnight, and breezy for a time over Ulster with some showers, but these dying out gradually, with the fresh northwest winds easing.
"A dry clear night elsewhere. Lowest temperatures -1C to 3C, with frost forming quite widely, coldest of all over the southern half of the country, with a risk of a few icy patches."
Sunday will be dry and bright with highs of 11C.
However, temperatures will plummet overnight, with the weather chiefs warning of icy patches forming.
"Sunday night will be cold and frosty, with lows of -2C to 2C.
"Some icy patches are possible. Light northeast breezes will freshen in southern coastal counties later in the night."
