Met Eireann has issued a five-day weather advisory with freezing weather set to blast the country.
The national forecaster's alert comes into effect at midnight on Tuesday and will last until the same time on Sunday.
Snow is expected in parts of the country although it is not yet known how significant that could be.
The advisory says: "Turning colder from Wednesday with weather conditions becoming increasingly wintry for the rest of the week. Risk of frost and icy conditions, with falls of sleet or snow at times."
And temperatures are predicted to drop as low as -4C on Friday night in the coldest period of the chilly snap throughout the weekend.
A Met Eireann forecaster added: "Turning very cold through Friday evening with a widespread frost setting in. Showers will continue in the northwest overnight.
"Lowest temperatures of -4 to -1 degrees in light breezes allowing fog to develop.
"Remaining cold over the weekend with sunny spells and scattered showers with wintry falls. Highest temperatures ranging from 2 to 6 degrees. Widespread frost both nights with temperatures dropping to -4 degrees in places."
Status yellow rainfall warnings are already in place for Connacht, Ulster and other northerly areas today with torrential rain expected to fall.
