ROAD users are being urged to exercise extreme caution as the first significant frost of the year is expected overnight tomorrow as temperatures plummet to below zero.
Met Eireann says the mercury will dip below zero in most areas and even lower inland late tomorrow and early Monday.
"You need to be mindful when it's a crossover period," said RSA spokesman Brian Farrell.
The RSA is also advising motorists to plan for winter driving and check to ensure that tyres are properly inflated and the car is serviced.
Motorists were also advised to travel with spare fuel, high visibility vests, a shovel, tow rope, car blanket and emergency food, clothing and water supplies.
Drivers should also travel with sunglasses as low winter sun can be blinding.
Meanwhile, Met Eireann is forecasting a wet and blustery weekend and week ahead with just occasional sunny periods.
"It's going to be a mixed bag," forecaster Eoin Sherlock told the Irish Independent.
A depression coming in from the Atlantic this morning will bring very heavy rainfalls, between 10 and 12mm, in the West. The rain will continue to move eastward across the country before clearing in the late afternoon, he said.
But it won't stay dry for long as a band of heavy and possibly thundery showers moves in tonight, he added.
Temperatures will also stay cool, with today's high not expected to exceed 11C; and it will be even colder tonight when the mercury will drop to between 2C to 4C.
Tomorrow will also get off to a wet start in the south, while the rest of the country can expect occasional showers with temperatures remaining cool at just eight to 10C. However, it should remain dry in the north and north west of the country.
But the winter chill will really start to set in tomorrow night after the rain pushes off over the Irish sea and a cold northerly airflow moves in overnight.
Temperatures will drop to zero in most areas and -1C to -2C further inland with widespread ground frost, Mr Sherlock said.
Temperatures will gradually start climbing on Monday as more rain moves in from the west coast but it will remain cool with highs of just eight to 11C.
"It looks like the Atlantic influence is back," Mr Sherlock said. "It sets the tone for another unsettled week."