Met Office warns householders to weight things down in gardens because of high winds
The 31.4C reading in Armagh on Thursday is provisionally the highest temperature on record, the Met Office says.
It beats the previous record on Tuesday, and the one before that, set on Sunday.
Until this heatwave, the record in the province had stood for 45 years.
At the same time, Scotland and Wales on Thursday recorded their highest temperature of the year so far.
But the heatwave that has engulfed the UK will abruptly switch to stormy weather in southern England this weekend, forecasters are warning.
Winds are expected to be so strong in southwest England that the Met Office warned householders to weight things down outdoors.
Roads started melting this week after the Met Office on Monday issued its first ever extreme heat warning for most of southern and central England and Wales.
An amber warning over extreme heat, lasting until Friday, is also in place in Northern Ireland.
The top temperature in England was 30.7C, in Derbyshire.
In Scotland a temperature of 29.3C was recorded at Threave in Dumfries and Galloway on Thursday, the Met Office said.
But forecasters are predicting strong, gusty winds in the southwest on Friday.
“With strong winds forecast tomorrow for some of us, have a think about what you might have around the garden that could be at risk. Think about moving or securing things,” the Met Office tweeted.
“A rain warning comes into effect from Friday night, with flooding possible in places over the weekend in central and southern England,” it added.
It also issued a yellow warning for rain for much of central and southern England for Sunday, with the potential for transport disruption.
At least 17 people have died in water since Saturday during the scorching temperatures across the UK, according to the Royal Life Saving Society UK.
Lee Heard, of the charity, said: “The difference between the air temperature and water temperature can literally take your breath away; this is called cold water shock. It is silent, invisible and deadly.”
Animal-lovers said they were disgusted by workers forcing donkeys to give rides on a beach in Weston-Super-Mare in the sweltering conditions.
Colin Bawden said: “It’s disgusting. I show dogs but I wouldn’t put them out in this weather, I would keep them in the cool. It seems wrong for them [donkeys] to be working on the hottest day when there is a warning in place.”
In the United Arab Emirates, which receives only about 4in of rain a year, scientists are using electrical charges from drones to burst clouds.
England reached its hottest temperature of the year on Tuesday when 32.2C was recorded at Heathrow Airport in west London.
The changing climate is making searing, deadly heatwaves more frequent and more intense, scientists say.
G20 environment and energy ministers meeting in Naples made little progress on Thursday on how to reach climate goals, officials said, with a cluster of countries resisting firm commitments.