A nationwide snow and ice warning is now in effect, bringing icy and hazardous conditions across the country.
The yellow warning will came into effect at 6pm on Saturday with falls of hail, sleet and snow expected.
The warning will remain in place until midday on Sunday.
A status yellow snow/ice warning was in place for Cork, Kerry, Clare, Limerick, Galway, and Mayo earlier today.
This warning expired at 6pm, but the area will be covered by the latest update from Met Éireann.
Snowfall in the west of the country this evening is already causing disruption and closing roads.
Gardaí are warning Clifden in Galway is "impassable" as is the Conor Pass on the Dingle Peninsula in Kerry.
The Road Safety Authority is urging both drivers and people exercising within their 5k to be careful of slippery road surfaces.
Spokesperson Brian Farrell said: "We would advise road users to check local traffic and weather updates before they head out on a journey over the weekend, just to be sure they're not likely to encounter any severe weather."
Director of Consumer Affairs at the AA, Conor Faughnan, says there are a number of precautions people can take.
"We are likely to have frost and ice in many counties countrywide, particularly on secondary roads," Mr Faughnan said.
"That's very dangerous, so we would implore motorists to recognise how dangerous conditions are and reduce the speed.
"The single most important safety component in a modern car is the driver's right foot.
In the North, a similar warning has been issued for Antrim, Armagh, Down, Fermanagh, Tyrone, and Derry.
The Met Office's yellow alert for snow/ice is in place from 4pm on Friday, until 10.30am on Saturday.
Earlier, it was forecast that Ireland is set for a bitterly cold weekend with temperatures set to plummet to -4 in parts overnight.
The remainder of the weekend will be cold with showers of sleet and snow.
Alan O'Reilly from Carlow Weather says people will be waking up to snow on Sunday.
"Down to -4 tonight and a very cold day ahead again tomorrow," he said.
"A band of sleet and snow crossing the country tomorrow night, with many people waking to a nice covering of light snow on Sunday.
"Just a dusting in some areas but certainly a snow covering for many on Sunday morning with another bitterly cold day ahead."