An air temperature of 20.1 degrees, recorded in Dooks, Co Kerry, on Sunday was the highest ever recorded in Ireland for the month of November.
Temperatures in parts of the State on Sunday were more than 10 degrees higher than the average for this time of year.
The previous record high for November was 20 degrees, recorded in 1946 on the 4th of the month at Rathfarnam Castle, Met Éireann said. The average temperature at this time of year is 9.3 degrees.
“It was a ridge of high pressure over Ireland [on Sunday] that extended from an anti-cyclone over south east Europe and which generated slack southerly winds in a tropical continental air mass,” said Aidan Murphy from Met Éireann’s climate enquiries office. “That then produced higher temperatures for this time of year for Ireland.”
He added that the temperature of 20.1 degrees may have been exceeded elsewhere in the country but this wouldn’t be known until the end of the month when data from all weather stations has been collected.
The UK’s November temperature record was also broken on Sunday with 22.4 degrees recorded in mid-Wales. The record had been 21.7 degrees, also in Wales, in 1946.
Temperatures were boosted in the UK by the same southerly winds from the continent, bringing warm air, settled conditions and sunshine.
However, the British Met Office issued a yellow warning for fog on Sunday evening with conditions leading to flight cancellations at Heathrow and other airports.
Air passengers faced further disruption on Monday when dozens of flights, including six from Dublin into London, were cancelled because of fog.
Similar conditions across the continent also caused disruption for air travellers with Brussels, Paris-Charles de Gaulle, Frankfurt and Hamburg airports affected by low visibility.
In Ireland, temperatures fell slightly on Monday although it remained warmer than usual with highs of about 13 to 16 degrees after a foggy morning.
Another dull and misty morning on Tuesday is forecast to give way to sunny spells and top temperatures of 11 to 15 degrees but Mr Murphy said low air pressure on Wednesday is likely to bring wetter conditions.
Overall cloudier weather on Thursday should bring outbreaks of rain to many areas. Rain, mainly along the west coast of the country could turn heavy on Friday but eastern counties should remain dry.