Motorists are being urged to be on the alert for dangerous conditions this evening.
Met Éireann says temperatures will drop to -3 C with some patches of freezing fog also. A yellow weather warning is in place until 10am tomorrow morning.
Wednesday is expected to be very cold with further rain, sleet and snow over Leinsters and parts of Munster.
Some areas of Munster can expect three centimetres of snow overnight.
Top temperatures are going to be around 4-8 C.
Thursday will remain cold with northeasterly winds along eastern and southern coasts.
It may brighten up during the day with some sunny spells and just a few scattered showers. Temperatures will be a little higher reaching 7-9 C.
Thursday night will be cold and dry, but is unlikely to hit freezing temperatures.