Temperatures dipped as low as almost -6 degrees last night, meaning the country experienced its coldest temperatures so far this winter.
Met Éireann forecaster Joan Blackburn said there are still frosty and foggy conditions expected over the next number of days.
Speaking this morning on RTÉ Radio One, the forecaster reminded people that the Status Yellow low temperature warning from overnight will not expire until 11am.
“We had the coldest temperatures so far this winter last night,” she said.
“A low of -5.7 degrees was recorded in Mullingar.
“We’ve a very cold and icy start this morning and the warning remains in place for the next few hours.
“The frost and fog will clear gradually and we can expect dry and bright conditions for the rest of the day, with sunshine for some time.
“Highest temperatures will be between three and four degrees in Ulster and seven and eight degrees in Leinster,” she added.
Temperatures are not expected to fall as low tonight, but there will be a sharp frost and some fog and icy patches in the morning.
Highest temperatures tomorrow are expected to reach between six and nine degrees.
More frost and fog can be expected on Monday night, the majority of which will be in the midlands, south and east.
Ms Blackburn said the rest of the week is expected to be “mostly dry, but rather cloudy, especially in northern and north-western counties”.
“Cloudy conditions by night will tend to limit the frost a bit,” she continued.
“Then we have a much more unsettled picture for next weekend.
“Take care if you’re out and about,” she added.