There will be frost and icy patches today across the country, and forecasters are advising drivers to take care.
Heavy and possibly thundery showers will also fall today, moving from the west to the east. Showers will become isolated in the west by this evening.
Joanna Donnelly from Met Eireann said: "It's not a great day today, it's going to be fairly cold. But temperatures are going to start pick up to six to nine degrees by this evening."
"Showers are going to pull back to the West coast and most places are going to become dry."
However, she warned: "There will be ice on untreated surfaces in all areas."
Temperatures will plummet "fairly rapidly to below zero overnight," Ms Donnelly said.
For tomorrow, rain will fall nationwide and this will bring milder temperatures.
"It'll start to get milder tomorrow and it'll be raining. Once the rain starts the temperatures will pick up again to around nine to eleven degrees."