Cliff Notes
- Current Heatwave: Most of Europe is experiencing extreme temperatures under a “heat dome,” with highs expected to reach 34C (93.2F) in the UK, potentially surpassing tropical regions like Mexico and Jamaica.
- Impact of Heat Dome: This high-pressure system traps hot air and blocks cooler weather, leading to persistent heat and “tropical nights” where temperatures remain above 20C (68F), particularly affecting southern and eastern England.
- Climate Change Connection: While heat domes are not new, climate change is intensifying their effects, increasing their frequency and severity, with scientists urging proactive measures to mitigate health risks and environmental impacts.
Weather: What is a ‘heat dome’ – and how long is it set to affect the UK?
Most of Europe is right now baking in a so-called “heat dome” – conditions a bit like a pizza oven, which are scorching Spain, France, Italy, Greece and beyond.
Meanwhile, temperatures in the UK could soar to a rare 34C (93.2F) today – meaning it could be hotter than Mexico, Barbados and Jamaica.
So, what’s going on with our weather?
What is a heat dome?
A heat dome forms when an area of high pressure lingers over a region for days or weeks.
This pressure traps hot air – like the dome of a pizza oven or a lid on a saucepan – and bakes the air and land beneath.
As the ground parches, it absorbs heat – making conditions hotter still.
The dome of high pressure also blocks out clouds and cooler air, resulting in clear skies and persistent heat.
What effect is the heat dome having on the UK?
The current heat dome is hovering across most of Europe, while the UK sits just on the cusp of it.
That means the same high pressure bringing plus 40C (104F) temperatures to southern Europe is also roasting southern and eastern England on Monday and Tuesday.
Temperatures could soar to 34C (93.2F) in London and the southeast today – a “relatively rare event, with just a handful of days [of 34C] since the 1960s”, according to Met Office scientist Dr Amy Doherty.
And these regions are due to sweat through a “tropical night” on Monday evening – when temperatures do not drop below 20C (68F), making it much harder to sleep.
This heat will be pushed away to the southeast on Tuesday night, as a cold front moves through southeastern England.
Northern and western Britain sit outside the area of high pressure, hence conditions there are cooler and wetter.
Are heat domes becoming more common?
The (scientific) jury is still out, says climate scientist Dr Michael Byrne, from the University of St Andrews.
“Some research suggests heat domes will become more common as climate warms, with more frequent heatwaves as a result” but there is no scientific consensus yet, he says.
“But what is crystal clear is that climate change is loading the dice such that when a heat dome does occur, it brings hotter and more dangerous temperatures,” he adds.