Forecasters are warning of "widespread frost" and a risk of "wintry falls" later this week as temperatures plunge.
Rain, sleet and icy patches are set to arrive across the country as the mercury is expected to plummet to lows of -2C at night.
And daytime temperatures aren't much better, with highs of just 8C or 9C most days.
Monday will be cold and blustery with sunny spells and occasional showers.
The showers will be most frequent and heaviest in the west and north with a risk of hail and thunder while the best of the dry spells will be in the east.
Highest temperatures will reach 6C to 9C but strong and gusty west to northwest winds will make it feel quite chilly.
Met Eireann has warned that tonight will be cold and blustery with occasional showers most frequent across the north and west.
Tuesday will see a mix of showers and dry and sunny spells with highs of 7C to 9C. But the showers will merge into longer spells of rain in parts of the north for a time
And the risk of frost and sleet will increase as the week goes on.
Wednesday will be cold with daytime highs of 5C to 8C and heavy rain, potentially turning to sleet on higher ground.
The outbreaks of rain and sleet will continue overnight across much of the country .
On Wednesday night, there'll be a "widespread frost" combined with a risk of "wintry falls" on higher ground. Temperatures will drop to lows of -1C.
By Friday night, temperatures will dip to lows of -2C.
The outlook for the coming days is for "cold and unsettled with rain or showers for the coming days but some dry sunny periods expected towards the end of the week."
