Suncream bottles were dusted off as families took to the seaside armed with buckets and spades and eager to enjoy some long-awaited hot weather.
Helen's Bay in Co Down was one popular hotspot, with young families enjoying a splash while teenagers topped up their tans.
Further inland, the smell of barbecues wafted its way through towns. Parks were crammed with workers having a bite to eat in parks and hundreds filled Botanic Gardens in sun-kissed Belfast.
The soaring temperatures reached 21 degrees in Castlederg in Co Tyrone, as locals took in the rays and welcomed the dramatic change in weather from the weekend.
The warm temperatures follow the coldest spring in 34 years after the wintry weather held its grip, wreaking havoc throughout Northern Ireland.
Snow blizzards in March led to tens of thousands of animals dying during the lambing season, with farmers claiming it has been the worst winter they experienced.
They weren't wrong – it was the coldest March on record here.
Yesterday's hot weather gave us a tantalising hint that summer is just around the corner – and hopefully here to stay.
The Met Office reported that the warm weather is set to continue for the next few days at least, with a maximum temperature of 19C forecast today.
Thursday and Friday are set to be dry and sunny and warm in the sunshine.
However, there's no guarantee that the high temperatures will continue throughout the next few weeks.
Experts are advising locals to take advantage of the sun now as it may not last.
A warning has also been sent out to hay fever sufferers as the warm weather means that tree and grass pollen levels will remain moderate.
Last Wednesday's top temperature hit 20.7C, which was recorded at Stormont.
But the UK as a whole has not beaten its previous hottest temperature this year, which was 23.8C in Derbyshire on May 7, although the final figures are yet to be confirmed.