Met Eireann has warned of freezing temperatures as it issues its predictions for the rest of this weekend and the coming week.
The national forecaster said the mercury will dip to a chilly -2C tonight with widespread frost expected.
Today will be cold with sunny spells and scattered showers – a few of them possibly heavy – and there is a risk of hail and a slight risk of thunder.
Highest temperatures will reach 7C to 10C in mostly moderate to fresh northwest winds.
Looking ahead to tonight, a forecaster said: "Mainly dry, with clear spells, but very cold, with widespread frost. Lowest temperatures of -2C to 1C, coldest in the eastern half of the country."
Meanwhile, Monday will be dry but cold in most parts at first, with bright spells, but outbreaks of rain will move in across Connacht and west Ulster in the afternoon, spreading eastwards through the day and becoming patchier towards evening.
Temperatures will reach highs of 8C to 11C after a cold and frosty start.
Southwest winds will be mostly moderate to fresh, but stronger along Atlantic coasts.
St Patrick's Day, March 17, looks set to be a very mild and cloudy day with temperatures reaching highs of 14C to 15C.
However, Connacht and the western Ulster will be lashed by widespread rain, turning heavy at times.
