Snow and sleet caused difficult road conditions for evening commuters in the midlands on Wednesday amid the first fall of the winter.
AA Roadwatch advised motorists to exercise "extreme caution" on the M7 between junctions 14 Monasterevin in Co Kildare and junction 15 Ballybrittas in Co Laois.
Sleet and snow have been affecting conditions in parts of Laois, Carlow and Kildare, particularly around Athy, Stradbally and Carlow town.
Met Éireann forecaster Vincent O'Shea said an Atlantic front is meeting very cold air over Ireland and it is falling in some places as snow. "It is very unusual for so early in the year," he said.
Mr O’Shea added that freezing temperatures on Wednesday night into Thursday morning could turn snow and sleet into ice and create treacherous conditions on the road. Temperatures will fall to minus 1 degrees in midlands areas.
A status yellow rain warning is already in place for counties Carlow, Kilkenny, Offaly, Kildare, Laois, Tipperary and Wicklow.
The band of rain was expected to lead to some spot flooding, before turning to sleet and snow later.
The warning is in place from 2pm on Wednesday until 2am on Thursday.
Thursday will be another cold day with the chance of show showers along northwest coasts and parts of east Leinster. Highest temperatures will only range between 4 and 8 degrees, but it will feel even colder in a biting northerly wind.
Temperatures will again fall below freezing in many places at night with a sharp frost developing on both Thursday night and Friday morning.
Winds will moderate on Friday, but it will still be cold on Friday night with a sharp frost inland and the risk of icy patches. A few patches of mist may also form.