Temperatures are due to drop by up to 10 degrees over the next few days, writes Lorna Siggins.
Met Éireann is anticipating a “pretty cold spell after an incredibly mild winter so far”, according to its head of forecasting, Gerald Fleming.
The Garda press office has issued a warning to road users, urging safe driving. It has also advised drivers against undertaking any unnecessary journeys.
Conditions were not expected to be anything like those of December 2010, when temperatures plummeted and the island was carpeted in snow, but there would be frost and icy patches and some wintry showers, Mr Fleming said.
“It won’t be severe, but there will be some snow on high ground, mainly in the west and northwest, and with temperatures below zero at night,” he added.
January’s air temperatures have been on average about four degrees Celsius above the same period last year.