The world saw multiple temperature records tumble on Monday as unprecedented heat waves scorched parts of the Northern Hemisphere.

The dangerously high temperature triggered health warnings and fanned wildfires in the latest stark reminder of the effects of global warming.

From North America to Europe and Asia, people gulped water and sought shelter from the sweltering heat, with the mercury expected to reach new highs in several places in the next few days.

Europe, the globe's fastest-warming continent, was bracing for its hottest-ever temperature this week on Italy's islands of Sicily and Sardinia, where a high of 48 degrees Celsius (118 degrees Fahrenheit) is predicted, according to the European Space Agency (ESA).

"We're from Texas and it's really hot there, we thought we would escape the heat but it's even hotter here," Colman Peavy, 30, said as he sipped a cappuccino at an outside terrasse in central Rome with his wife Ana at the start of a two-week Italian vacation.

With June already having been the world's hottest on record, according to the EU weather monitoring service, Mother Nature seemed intent on July not falling far behind.

China reported a new high for mid-July in the northwest of the country, where the temperature reached 52.2 degrees Celsius in the Xinjiang region's village of Sanbao, breaking the previous high of 50.6 degrees Celsius set six years ago.

In nearby Turpan city, where ground surface temperatures sizzled at 80 degrees Celsius in some parts, authorities have told workers and students to stay home and ordered special vehicles to spray water on major thoroughfares, the meteorological body said.

In Cyprus, where temperatures are expected to remain above 40 degrees Celsius through Thursday, a 90-year-old man died as a result of heatstroke and three other seniors were hospitalized, health officials said.

In Japan, heatstroke alerts were issued in 32 out of the country's 47 prefectures, mainly in central and southwestern regions.

At least 60 people in Japan were treated for heatstroke, local media reported, including 51 who were taken to a hospital in Tokyo.

The heat was enough for at least one man to dispense with social mortification in Hamamatsu City.

"It's honestly unbearable without a parasol, although I have to admit it is a bit embarrassing," he told national broadcaster NHK of the umbrella in his hand.

Japan's highest-ever temperature was 41.1 degrees Celsius first recorded in Kumagaya city in 2018.

'Oppressive' US heat

In western and southern states in the U.S., which are used to high temperatures, more than 80 million people were under advisories as a "widespread and oppressive" heat wave roasted the region.

California's Death Valley, often among the hottest places on Earth, reached a near-record 52 degrees Celsius Sunday afternoon.

In Arizona, the state capital Phoenix recorded its 17th straight day above 43 degrees Celsius, as temperatures hit 45C degrees Celsius on Sunday afternoon.

"We're used to 110, 112 (degrees Fahrenheit) ... But not the streaks," Nancy Leonard, a 64-year-old retiree from the nearby suburb of Peoria, told AFP. "You just have to adapt."

Southern California was fighting numerous wildfires, including one in Riverside County that has burned more than 7,500 acres (3,000 hectares) and prompted evacuation orders.

Historic highs forecast

In Europe, Italians were warned to prepare for "the most intense heat wave of the summer and also one of the most intense of all time," with the Health Ministry sounding a red alert for 16 cities including Rome, Bologna and Florence.

Temperatures were due to hit 42 degrees Celsius-43 degrees Celsius in Rome on Tuesday, smashing the record of 40.5 degrees Celsius set in August 2007.

Nevertheless, visitors thronged to tourist hot spots like the Colosseum and the Vatican.

"I'm from South Africa. We're used to this heat," said Jacob Vreunissen, 60, a civil engineer from Cape Town. "You have to drink lots of water, obviously wear your hat and that's about it."

Greece saw a respite Monday, as temperatures eased a bit and the Acropolis in Athens resumed its regular opening hours after shutting for a few hours during the previous three days. But a new heat wave was expected from Thursday and meteorologists warned of a heightened risk of wildfires amid strengthening winds from the Aegean Sea.

In Romania, temperatures are expected to reach 39 degrees Celsius on Monday across most of the country.

Little reprieve is forecast for Spain, where meteorologists warned that "abnormally high" temperatures on Monday, including up to 44 degrees Celsius in the southern Andalusia region in what would be a new regional record.