Snow is falling in some parts of the country - with a Status Yellow weather warning in place.
Met Éireann says there's a significant risk of frost and ice on roads today as temperatures will only reach between 3 and 6 degrees.
Forecaster Deirdre Lowe says scattered snow showers are likely - mainly in Connacht and Ulster.
"A dusting of snow on lower levels anywhere is possible during the course of today, but the bulk of it will be on high ground."
Motorists are being urged to drive with care today, with widespread icy patches on roads.
Black ice is a particular danger on sheltered roads.
Road Safety Authority CEO Moyagh Murdoch says it is also important to remove all ice and snow from your car.
"That means to make sure to have the scraper in their car and the de-icer, and also if they're heading off in the morning and the windows are frosted up, to make sure they get them properly de-iced."