Jeff Masters, a meteorologist and co-founder of Weather Underground, an online news service, says the reason more temperature records are not being kept is because the process is too time-consuming. A typical example of this is that efforts to reanalyze every named Atlantic storm since 1851, which began two decades ago, have so far only reached 1965.

“There are hundreds of temperature records in the US alone that would not survive re-analysis,” said Dr. Masters. “The most famous of these is the hottest world record temperature in history of 134 degrees Fahrenheit in 1913 in Death Valley.”

Two extreme weather experts, William T. Reid and Christopher C. Burt, have argued on the Weather Underground site that the 1913 reading was “impossible from a meteorological point of view,” in part because it was inconsistent with other observations in that part Death Valley in the same week. They say the man who recorded the temperature at Greenland Ranch, California, seems to have retrospectively “knowingly or accidentally” exaggerated the readings, and that he may not even be there at the time.

But Randall Cerveny, who leads the World Meteorological Organization’s efforts to research and review global weather records, said in an email that the 1913 reading is still considered “the hottest temperature recorded for the United States and the world” was recognized.

Dr. Cerveny, who teaches geographic science at Arizona State University and worked with Mr. Burt to debunk the 1922 Libya data set, described Mr. Burt and Mr. Reid’s research on the 1913 Death Valley data set as “presumptive, not new, evidence . He added that the US Climate Extremes Index, a NOAA project, has also chosen not to investigate it.

“We do not reject records without solid evidence that they are inaccurate,” he said.

Referring to more recent Death Valley records, Dr. Cerveny that the WMO is still trying to verify a 129.9 degree value in this range on August 6, 2020.

If confirmed, it would be the third highest temperature ever recorded on Earth and the second highest in the United States. But dr. Cerveny said the investigation will “take a while” because his team tested the temperature sensor that made the measurement.