The reading may be the hottest since 56.6C was taken at the same place in 1913 – but the accuracy of that has long been disputed.
A temperature of 54.4C (129.9F) has been recorded in California during an intense heatwave in what could be the hottest reading ever reliably taken on the planet.
An automated station for the United States National Weather Service at Furnace Creek in Death Valley recorded the extreme heat at 3.41pm on Sunday.
If verified, it would be the hottest weather since 56.6C (134F) was registered at the same place on 10 July 1913 – but the accuracy of that reading has long been disputed by experts.
The World Meteorological Organization (WMO) installed the 1913 reading as the Earth’s hottest after an investigation dismissed a temperature of 58C (136F), which was said to have been recorded in Libya in September 1922.
Another older reading of 55C (131F) taken in Tunisia in July 1931 has also been challenged.
In addition, the 1913 Death Valley heat has been questioned as “essentially not possible from a meteorological perspective”.
Some experts believe modern readings of 54C (129F) at Death Valley on 30 June 2013 and in Kuwait in 2016 and Pakistan in 2017 are the most reliably recorded top temperatures on the planet.
But it still means Sunday’s extreme heat at Death Valley could see the conditions crowned as officially the hottest on record.
As the temperature soared, humidity fell to just 7%. Death Valley is close to the Californian border with Nevada and is the driest and hottest location in the US.
Professor Randy Cerveny leads a WMO group which archives climate extremes and believes Sunday’s recording is “legitimate”.
In an email to the Washington Post, he wrote: “Everything I’ve seen so far indicates that is a legitimate observation.
“I am recommending that the World Meteorological Organization preliminarily accept the observation.
“In the upcoming weeks, we will, of course, be examining it in detail, along with the US National Climate Extremes Committee, using one of our international evaluation teams.”
It came as a warning was issued in California due to wildfires burning near the Nevada border.