A temperature of 33C was recorded at the Phoenix Park in Dublin on Monday.
This was just 0.3C cooler than the all-time high of 33.3C which was recorded at Kilkenny Castle on June 26, 1887.
A status yellow high temperature warning remains in place across the country as it faces another day of high heat.
🌡️ Phoenix Park today 🌡️
▶️Recorded its highest ever temperature - 33.0°C
▶️12.8°C above its long-term average
▶️The 2nd highest temp on record for Ireland
Read all about the temperature records broken in July & Met Éireann's new Climate Services Division https://t.co/lTUJldCSR5 pic.twitter.com/fxASZf8kkD
— Met Éireann (@MetEireann) July 18, 2022
The Phoenix Park temperature on Monday marks the highest recorded in the 21st century, overtaking 32.3C in Elphin, Co Roscommon on July 19, 2006.
It was also higher than any temperature recorded in the 20th century, and the highest temperature ever recorded in the capital, according to Met Eireann data.
It said: “Phoenix Park has broken the highest 21st temperature record with 33C which is Ireland’s highest of 2022 so far and 12.8C above normal.
“This is only 0.3C below the all-time 135-year-old record set at Kilkenny Castle in 1887. Temperatures may still rise further.”
The rise in temperatures has forced Met Eireann to issue a hot weather warning that is to last until midnight on Tuesday.
It said that exceptionally warm weather will occur over Ireland on Monday with daytime temperatures of 25 to 30 degrees generally and possibly up to 32 degrees in places.
Night time temperatures will range from 15 to 20 degrees.
People went to enjoy the heat in Phoenix Park.
Families flocked to the zoo as temperatures reached the low 30s, with children and adults buying 99s to help cool off.
Phoenix Park has broken the highest 21st temperature record with 33.0°C which is Ireland’s highest of 2022 so far and 12.8°C above normal. This is only 0.3°C below the all-time 135 year old record set at Kilkenny Castle in 1887. Temperatures may still rise further .... pic.twitter.com/bJAhdPtMea
— Irish Observational Climatology (@METclimate) July 18, 2022
Jackie, who works at the toy stall across from the zoo, said that her stalls are in the shade now, but the sun will come around by 4pm.
She said: “It’ll be boiling. It’s always very hot in the evenings here. But there’s a nice little breeze coming up the hollow now.”
Some sun worshippers bathed in the heat, while others retreated to shaded picnic benches to take a break from the unusually high temperatures for Ireland.
There appeared to be fewer dogs being brought for walks in the large park than normal, after people were warned not to expose their pets to the heat during the Status Yellow warning.
A cool breeze and bouts of overcast weather at the park provided some respite from the heat.
31-year-old Tadgh was out for a run in the Phoenix Park as the news broke that the temperature record for the year was broken.
“I could do without it,” he said of the heat.
“It’s hot enough, It’ll be fine if it stays that way,” he said, adding that he does not want it any hotter.
“I’m going slower than I usually go, the heart rate is higher, walking more than I usually do.
“I’m taking it easy, going as slow as I need to.”
In the southside of the city, people headed in their droves to the Forty Foot in Sandycove.
Aimee McDonagh, 27, who swims at the famous bathing spot regularly, said: “It’s absolutely nuts. All these blow-ins.
“All these kids with their speakers. I feel like an aul-wan. It’s like the middle of Ibiza. It’s good craic though.”
The Dublin hairdresser added: “Normally it’s very calm here but not today. I don’t think I’ve ever seen it like this.”
In nearby Dun Laoghaire, fewer people than usual were walking the East Pier.
Dubliner Derek Hand, 57, who was fishing off the pier with some friends, said it was “quieter than normal”.
“Everyone’s gone to the beach with all their kids,” he said.
The fish weren’t biting but he was looking on the bright side as he was “getting the colour”.
“Normally I take the T-shirt off but enough is enough – I’ve had too much. I don’t want to blister,” he added.
Met Eireann said that Tuesday will continue to be very warm over the eastern half of the country, with highest temperatures of 22-26 or 27 degrees, with cooler and fresher elsewhere though with highs of 16-22 degrees.