Temperatures have been steadily climbing for several days now, reaching 32C (89.6F) at Northolt, northwest London, at 3pm on Monday.
The same heatwave is affecting France, Portugal and Spain, where temperatures hit 43C (109F) near Seville on Sunday.
Look at a map of Europe and you can see a heat blob more than 1000 miles across.
The highest temperature ever recorded in the UK was 38.7C (101.6F) in Cambridge on 25 July 2019.
We’re still well short of that, but there is a chance the record will be smashed later in the week.
Of course, it’s mid-summer, so it’s bound to be hot. But is it getting hotter more often?
Below are the peak temperatures of every year back to 1900, colour coded from cooler blue to hotter red.
There are days over 35C (95F) scattered through the 20th century, but there is an emerging trend in the last decade or so of reds and oranges showing consistently higher peak temperatures.
The warming trend really stands out when you look at average temperatures for the whole summer, not just the one-off hot days.
Summer heat has been climbing since the last couple of decades of the last century: the five warmest summers on record have all been since 1976.
So a clear trend. But is it climate change?
Yes, says the Met Office. It looked at the summer of 2018, the joint warmest on record.
It found the chance of such a hot summer in a natural climate was just 0.5%. But because of greenhouse gases in the atmosphere, that had increased to 12%.
In other words, a record summer is almost 30 times more likely now as a result of climate change.
The warming trend will accelerate. By mid-century, the Met Office predicts a summer as hot as 2018 will happen every other year.
And if greenhouse gas emissions continue to climb as predicted, by the end of the century UK temperatures will peak at 40C (104F) or more once every three to four years.
Such sweltering heat is life-threatening – particularly for the young and old – when temperatures remain high for several days.
Heatwave deaths currently average around 2,000 a year. By 2050 they’re predicted to reach 7,000.
Living in Britain’s heating climate is going to be increasingly uncomfortable for us all. And deadly for some.