What is causing the dangerous heatwave in the US and will it affect the UK?

People cool off at Crown Fountain in Millennium Park, Chicago, as temperatures reached a record high of 97°F (36°C) on June 17, 2024  (Getty Images)
People cool off at Crown Fountain in Millennium Park, Chicago, as temperatures reached a record high of 97°F (36°C) on June 17, 2024 (Getty Images)

Many parts of the world are experiencing record temperatures this week, with heatwave warnings in the US, Europe, and beyond.

Tens of millions of people are facing an unexpected blast of extreme heat in the US, with temperatures of up to 37°C in cities such as Chicago this week.

The National Weather Service says the heatwave could continue into early next week and is “potentially the longest experienced in decades for some locations”.

New York Governor Kathy Hochul said earlier this week: “This is a time of significant risk, and we’re doing our best to make sure that all lives are protected.”

People play beach volleyball in Domino Park in Brooklyn, New York, as a heatwave hits the north-east US on June 18, 2024 (AFP via Getty Images)
People play beach volleyball in Domino Park in Brooklyn, New York, as a heatwave hits the north-east US on June 18, 2024 (AFP via Getty Images)

Meanwhile, European locations including Greece, Cyprus, and Turkey are similarly sweltering under 40-degree heat, which has caused wildfires, evacuations, and even deaths.

In the Middle East, more than 550 Hajj pilgrims reportedly died from heat-related causes as temperatures in Saudi Arabia soared to 51.8°C.

So what’s causing the extreme heat and could the UK also be affected?

What’s causing the US heatwave?

This week’s US heatwaves have been attributed to a heat dome — high pressure that lingers in the same area for several days.

High pressure means the warm air cannot rise and escape like it normally would, creating a dome effect that continues to warm the air below.

Wider climate change has exacerbated this, with studies suggesting that future heatwaves will be more intense and long-lasting.

Will the UK also have a heatwave?

A Sky News meteorologist said the UK weather had remained "disappointingly cool" while the rest of the world swelters.

Some parts of the country have also faced a washout, with rain and thunder dampening summer activities due to low pressure. According to the latest Met Office data, there are no heatwave warnings for the UK.

However, Met Office Deputy Chief Meteorologist Dan Harris said earlier this week there would be a “steady uptick” in temperatures in the coming days.

“In stark contrast to the first half of June, where temperatures have widely been below average, we are expecting to see a steady uptick through the second half of this week, rising to around or above average, and it will likely feel very warm for those in the sunshine,” he said.

“This initial spell of warm conditions isn’t expected to last too long, however, as it turns more changeable through Friday (June 21) and into the weekend with areas of cloud and rain spilling east across the UK.”

You can find out more about London’s weather next week (it is forecast to be hotter than the Algarve in the capital) and what causes heatwaves here.