The scorching heatwave that has swept the US south-east in recent weeks will soon spread to the country’s midwest and north-east regions, affecting nearly 250 million Americans.
Temperatures are stuck at 90F (32C) or above for at least the next week in much of the US, the National Weather Service (NWS) predicted. The NWS defines a heatwave as a period of temperatures exceeding 90F for two or more days, and this one could last until 26 June.
The NWS said: “The first heatwave of the summer begins Sunday over the middle of the nation, before spreading to the midwest and to the north-east by Tuesday then lasting most of next week,” with temperatures expected to approach 105F and break records, with very warm nights.
Soon, cities including Chicago, Indianapolis, Cleveland, Pittsburgh, Philadelphia and Boston may also see their hottest day of the year so far. And humidity is likely to be high.
The US south-east since last week has been sweltering under a so-called heat dome, which occurs when strong, high pressure traps hot air over a region, preventing cool air from traveling in and causing temperatures to rise on the ground and stay high. Such air pressure can also prevent cloud formation.
Experts say the human-induced climate crisis – sparked largely by the emission of greenhouse gases from burning fossil fuels, along with deforestation – is making heatwaves hotter and last longer around the world.
Phoenix, Arizona – the hottest US major city – reached 113F earlier this month, making it the city’s hottest day of the year so far. Last year was the deadliest on record for extreme temperatures in the city.
Extreme weather has also battered Florida.
Florida’s governor, Ron DeSantis, on Wednesday declared a state of emergency in several counties following torrential rain from storms that have caused severe flooding.
As the state grapples with extreme weather, the Republican governor in May signed legislation that erases references to the climate crisis from state law.
“We’re restoring sanity in our approach to energy and rejecting the agenda of the radical green zealots,” DeSantis wrote on X. The legislation will take effect on 1 July.
South Florida has also suffered under the scorching sun recently as record-high temperatures came early,
Nevertheless, DeSantis signed a law prohibiting any municipalities in the state from passing heat-protection requirements for workers, such as employers being obliged to provide water and shade.
Large swaths of Texas, most of which is uniquely powered by its own electrical grid, suffered power outages in the midst of severe heat in May due to the increased demand.
And nearly 340,000 energy customers in Puerto Rico were without power on Wednesday night. The mayor of San Juan, Miguel Romero, has declared a state of emergency.
