Excessive heat warnings and heat advisories have been issued for more than 170 million Americans as heat index temperatures in many spots are expected to rise well past 38 °Celsius through tomorrow afternoon, the National Weather Service (NWS) said.
Some of the nation’s biggest cities, including Chicago, New York, and Philadelphia, have opened cooling centres in public libraries and community centres for those who are unable to escape the hot temperatures.
“Extreme heat can be dangerous to health, and even fatal,” the city of Boston said on its website after it declared a heat emergency, adding that its street outreach teams will provide water on their routes.
US city officials and forecasters are urging people to stay out of the hot weather as it has the potential to cause heat-related illnesses, especially for those working or participating in outdoor activities, people aged 65 and older, children, and those with chronic illnesses.
“Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,” the NWS said.
In Philadelphia, where the heat index could top out at 42 °C, officials extended public pool and spray grounds hours today and tomorrow.
In New York City, where the heat index was to reach 39 °C, officials posted a public service announcement video on social media urging owners to keep their pets well hydrated.
The growing frequency and intensity of severe weather are symptomatic of global, human-driven climate change that is fuelling extremes, experts in the field say, with heatwaves in much of the world expected to persist through August.
Last month was the hottest June on record in the US, dating back to 1850. It also was the 47th consecutive June and the 532nd consecutive month with temperatures above the 20th-century average, according to the weather service.
The hot weather through much of the US is expected to dissipate by late Saturday, leaving behind chances of thunderstorms and mild temperatures into next week, the weather service said.