ATHENS- Greece was Saturday facing its hottest July weekend in 50 years, with temperatures forecast to soar above 40 Celsius (104 Fahrenheit), while a record-breaking heat wave stretching across the southern United States was expected to expand in the coming days.
Tens of millions of people in the northern hemisphere have been suffering through intense heat this summer as the world appears headed for its hottest July on record.
Across the southern United States, about 80 million Americans will swelter in temperatures of 41C and above this weekend, the National Weather Service (NWS) said.
The country's worst heat of up to 46C is forecast for Phoenix, Arizona, which has seen a record-breaking three weeks in a row of highs above 43C.
There were hellish scenes in the city on Thursday when a fierce blaze erupted at a propane business near the international airport, sending tanks exploding into the air.
"Unfortunately, on a hot day like this, these propane tanks with that expansion of heat, they literally become missiles... They can travel upwards of 500 yards (metres)," Fire Captain Rob McDade told KPHO television station.
Tourists, meanwhile, have been flocking to Death Valley National Park, which straddles the border between California and Nevada, in order to post selfies with a temperature display outside the visitor center.
- Hottest absolute month -
Regardless, July 2023 is on track to be the hottest absolute month -- not only since records began, but also in "hundreds, if not thousands, of years," leading NASA climatologist Gavin Schmidt said.
The effects cannot be attributed solely to the El Nino weather pattern, which "has really only just emerged" and isn't expected to strengthen until later on in the year.
El Nino is associated with the warming of ocean surface temperatures in the central and eastern tropical Pacific Ocean.
Schmidt said the trend of extreme heat was expected to persist, "and the reason why we think that's going to continue, is because we continue to put greenhouse gasses into the atmosphere".
Greece, which is battling dozens of forest fires, warned people not to venture out unnecessarily due to the baking heat.
The exceptional temperatures also mean key tourist sites such as the Acropolis will be closed during the hottest part of the day.
"This weekend risks being the hottest registered in July in the past 50 years," said Panagiotis Giannopoulos, meteorologist with state broadcaster ERT.
"Athens is going to have temperatures above 40 Celsius for six to seven days, through to the end of July."
Such a prolonged spell of scorching temperatures is exceptional for the Greek capital.
Sunday is likely to see the city labour under temperatures as high as 44C, with the central region of Thessalia enduring 45C.
A 46-year-old man was meanwhile reported to have succumbed to heatstroke on the central Greek island of Evia after being admitted to Chalkida hospital, which said cardio-respiratory failure following exposure to high temperatures appeared to be the cause.
The national meteorological institute EMY earlier reported temperatures of 41C in the Attica region, which encompasses the capital Athens, and forecasting up to 44C in Thessalia.
Yannis Kallianos, meteorologist with private broadcaster Mega, spoke of an "interminable and powerful heatwave".
"According to latest forecasts, the heatwave could last until next Thursday or Friday," Kallianos warned, adding that strong northerly winds could also spark fires.
Authorities meanwhile reported firefighters were still battling 79 forest fires across the country, with their spokesman Vassilios Vathrakoyannis saying Greece would be on a state of alert through the weekend.
Greece is just one of a swathe of countries battling a prolonged spell of extreme heat around the globe in recent days.