Freezing fog and icy roads will make driving conditions treacherous tomorrow morning as the nation returns to work.
The warning to road users was issued as Met Eireann said the cold snap will continue until Wednesday night.
That will mean more severe night frosts and a risk of freezing fog, particularly tonight.
There will be more sleet and snow at times, but despite the biting winds there will also be dry, bright conditions with sunny spells.
Forecasters have said the bitterly cold weather will continue with snow expected to fall "over high ground, but at lower levels also, especially in parts of the midlands, north and east". Scattered thunderstorms have also been forecast for west Ulster, Connacht and west Munster.
Tonight will be mostly dry but very cold and icy with some pockets of freezing fog developing overnight, as the winds drop in the hours before dawn.
Frost and fog may linger in some areas throughout the day with afternoon temperatures of 1 to 4 degrees C.
Western coastal counties are most at risk for rain, sleet and snow tomorrow night but Tuesday's morning commute to work could also be icy on many national routes.
Yesterday road temperatures were below zero on a number of routes throughout the day as Eircom crews worked to restore service to customers following Storm Rachel. Some fixed line and broadband users are still without service following high winds and rain.
Meanwhile, the Cork-Kerry buoy measured an individual wave of 16.9m at 10am last Thursday. That's over 33 ft, the second highest on record at that location. The highest on record is a 19.1m wave (62ft) recorded on January 27 2013.