A status yellow snow and ice warning, as well as a wind alert, have been issued for Donegal, Galway, Leitrim, Mayo and Sligo.
Wintry showers are expected today and overnight with falls of hail, sleet and snow.
There will be icy stretches and accumulations of snow in some areas.
The warning is in place from 10am on Thursday morning until 7am on Friday.
Status Yellow - Wind warning for Clare, Cork, Kerry and Limerick— Met Éireann (@MetEireann) December 3, 2020
N to NW winds will strengthen on Friday evening and Friday night, gusting up to 100km/h with a slight risk of coastal flooding.
Valid: 16:00 Friday 04/12/2020 to 06:00 Saturday 05/12/2020https://t.co/l8JdKfwZt9 pic.twitter.com/XZxs2wiYg5
A wind warning will also be in place for Cork, Kerry, Limerick and Clare from 4pm on Friday until the early hours of Saturday morning.
North to northwest winds are expected to be strong Friday evening and Friday night, gusting up to 100km/h with a slight risk of coastal flooding.
Colder weather conditions are expected right across the country from this morning.
Heavy hail, sleet and snow showers are forecast for Co Donegal today, with a status yellow snow and ice warning in place until midnight tonight.
Met Éireann's issued a weather advisory for the rest of the country until Saturday, with sharp to severe frosts and icy stretches expected.
Bitterly cold day with widespread showers early on, some of which will be wintry. Showers will become confined to Atlantic counties, with spells of winter sunshine developing. Highs of just 3 to 6 degrees, in moderate westerly breezes. https://t.co/9gKN6SVok4 pic.twitter.com/wZZXITPrXA— Met Éireann (@MetEireann) December 3, 2020
Alan O'Reilly from Carlow Weather says it will feel significantly colder over the next two days.
"The biggest issue, apart from maybe the hail showers this morning will be the low temperatures tonight," he said.
"After those showers, it will result in very icy conditions tomorrow morning.
"Then we have a very strong north-west wind tomorrow as well so the wind chill factor is even going to make it feel much cooler again tomorrow so really going to be a bit of a shock to the system."
Cold today with widespread showers early on, some of which will be wintry, along with isolated thunderstorms. Highest temperatures of just 3 to 6 degrees, coldest over Ulster.
Very cold tonight with widespread frost and some icy stretches. Lowest temperatures of 0 to minus 2 degrees.
A widespread frost to begin on Friday with some icy stretches on untreated surfaces. Highest temperatures of just 4 to 7 degrees in freshening north or northwest winds.
Friday night will bring scattered showers, some wintry, especially in the north and east. Lowest temperatures of 0 to 4 degrees Celsius.
Saturday will bring further scattered showers. Highest temperatures of 5 to 8 degrees Celsius with an added chill factor.
Some lingering showers in eastern coastal areas, but most areas will be fully dry under clear skies. Very cold with lowest temperatures of -3 to +2 degrees, with a widespread sharp frost.