And new Easter Monday records were set in every other part of the UK too, as England enjoyed temperatures as high as 25 degrees, Scotland sizzled as the mercury reached 24.2 degrees, and Wales wallowed in 23.6 degree heat.
The previous Easter Monday record for Northern Ireland was set at Knockarevan in Co Fermanagh all the way back in 1984, with 21.1 degrees.
But the hottest temperatures since records began — over a century ago — was recorded by the Met Office in Armagh city yesterday, with 21.4 degrees.
And the warm weather is set to last until Wednesday.
Met Office forecaster Helen Roberts said: “There’s going to be a bit more cloud around on Tuesday — and possibly even one or two showers over more western parts of Northern Ireland .
“Those should be few and far between and aren’t likely to cause too many problems. Largely dry with hazy sunshine should be the main story until things go downhill on Wednesday with heavy, thundery showers reaching Northern Ireland by lunchtime.”
She said the temperature should be around 19 degrees in Northern Ireland on Tuesday.
Meanwhile, the PSNI has said a wildfire in the foothills of the Mourne Mountains is believed to have been started deliberately. The fire, which started on Sunday evening and rapidly spread to cover an area a mile wide at Tollymore Forest Park, forced the immediate evacuation of a nearby caravan park.
And the fire service were also called to a gorse fire in the Glens of Antrim yesterday, at an area around Altarichard Beauty spot. Five appliances were dispatched to the area on Monday afternoon. The operation was winding down last night.
This came amid further gorse fires in Co Donegal on Monday that forced the closure of the N56 between Dungloe and Gwedore.