Temperatures could hit below freezing during the night.
We can expect to see the first signs of the winter weather this week.
Temperatures are expected to plummet to as low as -3 or -4 degrees overnight towards the middle of the week, with forecasts of 1 or 2 degrees tonight.
It will also struggle to get above four degrees during the day.
Offaly's Cathal Nolan from Ireland's Weather Channel explains the shift in weather: