The West and North will bare the brunt of a cold snap that will begin shortly.
Met Eireann's yellow alert for Snow and Ice comes into force at 4pm and will run until late tomorrow morning.
It has warned of hazardous conditions for people setting off on a journey, with some isolated thunderstorms likely too.
Alan O'Reilly from Carlow Weather says this is because of a mix of freezing air and heavy downpours:
"It is going to turn much colder through this afternoon and into the evening, with some wintry showers - approaching from the west."
"So the combination of colder air and heavy showers will result in falls of sleet and snow through this evening into tonight and early tomorrow morning."