Overnight frost has left road conditions treacherous today with motorists warned to be aware of icy stretches on routes across the country.
The temperature plummeted to -6.6 degrees on the N2 in Monaghan while most road temps ranged between 0 and -5 degrees.
Drivers were urged to take particular care on secondary routes, reduce their speed and keep a safe distance from the vehicle in front.
AA Roadwatch said conditions are particularly treacherous in Donegal, especially around Letterkenny, Church Hill and Glenties.
Elsewhere, the N63 Longford to Roscommon Road is blocked just outside Longford town as emergency services deal with a fire.
Diversions are in place.