Latest: A status yellow snow-ice warning has been issued for five counties.
The warning for Wicklow, Donegal, Leitrim, Mayo and Sligo comes in to effect at 10pm tonight.
It is set to last until 11am tomorrow morning.
Met Éireann says there will be icy conditions and wintry showers which could lead to some accumulations of snow.
Status Yellow Snow - Ice warning issued for Wicklow, Donegal, Leitrim, Mayo and Sligo.
Valid from 22:00 hours Tue, 02-Apr-2019 until 11:00 hours Wed, 03-Apr-2019 pic.twitter.com/F3B4oCDHIV— Met Éireann (@MetEireann) April 2, 2019
Tonight there will be some falls of hail, sleet or snow with continuing risk of thunder.
Temperatures overnight will drop to between -1°C and 3°C.
In the morning, conditions will be bright and blustery with sunny spells and scattered showers of rain or hail.
Outbreaks of rain and sleet will move in across east Leinster and Ulster in the afternoon and spread to remaining areas in the evening.
Earlier: Frost and ice has affected many parts of the country overnight.
A status yellow warning is in place for Connacht, Cavan, Monaghan, Donegal, Longford and Louth until this afternoon.
Falls of hail and sleet may occur, with some accumulations of snow on higher ground.
Drivers are being advised to take extra care on the roads this morning.
"Slow down and leave that extra bit of distance between yourself and the car in front. It does take a good bit longer to stop your car in conditions like this," said Ann Marie Donnellan from AA Roadwatch.
"This morning frost has been reported as well around Carlow, Kilkenny and Kildare.
"Be extra careful if you are in an affected area, particularly on secondary roads, and in areas of higher ground it's likely to be that bit worse.