This story has been updated to reflect Death Valley’s new world record.
The average temperature in Death Valley last month was a stifling, suffocating 107.4 degrees. Since this story was originally published last week, we have determined it was the hottest month on record for the whole planet — not just the United States.
The average monthly temperature is a combination of highs and lows. Daytime temperatures in Death Valley are known to be excruciatingly hot. In fact, it is currently the location of the hottest temperature ever recorded on Earth, 134 degrees. (Note: This record is currently being challenged.)
But perhaps more alarming in this record is the month’s overnight temperatures — when things are supposed to cool down. The temperature didn’t fall below 89 degrees at any point in the month of July at Death Valley. On three nights, the “low” temperature was 102-103 degrees.
Brian Brettschneider, a climatologist at the International Arctic Research Center in Fairbanks, Alaska, started digging into this data last week. He found another location with a hotter month — King Khalid Military City in Saudi Arabia. In August 2014, the city’s average temperature was 41.91 degrees Celsius, or 107.44 degrees Fahrenheit.
At least, that’s what the Global Historical Climatology Network suggested.
“New evidence clearly shows the value from King Khaled to have been in error,” wrote Christopher C. Burt, a climatologist at Weather Underground, on Sunday. “Thus the Death Valley figure from this past July is, in fact, the warmest single month (average monthly temperature) reliably measured to date in the world.
In August 2014, King Khaled’s average average temperature was 41.91 degrees Celsius, or 107.44 degrees Fahrenheit, according to the GHCN database. But Brettschneider discovered the weather station in King Khaled was only recording temperature between 9 a.m. and 9 p.m. local time, which means half the day (importantly — the cooler half of the day) is missing.
Without the cooler temperatures, the daily average temperature records are erroneously warm, compared to surrounding stations.
Burt also noted that many cities in the West — and one in the Southeast — had their hottest month on record in July:
- Salt Lake City: 85.3 degrees (previous was 84.1 degrees in July 2013)
- Reno, Nev.: 80.5 degrees (tie with July 2014)
- Tonopah, Nev.: 78.9 degrees (previous 78.6 degrees in July 1931)
- Ely, Nev.: 71.8 degrees (previous 71.6 degrees in July 2003; however, an old and dubious report of 72.8 degrees in July 1908 is in the books)
- Bishop, Calif.: 80.8 degrees (previous was 80.6 degrees in July 2005)
- Miami: 85.7 degrees (previous 85.5 degrees in June 2010). This was anomalous for Florida. No other site in the state came close to breaking its record (i.e., West Palm Beach averaged just 84.3 degrees, almost a full 2 degrees short of its record 86.2 degrees set in July 2016).
The record-hot month in Death Valley adds to a growing group of locations to set all-time heat records this summer around the Northern Hemisphere:
In late July, Shanghai registered its highest temperature in recorded history, 105.6 degrees (40.9 Celsius).
In mid-July, Spain posted its highest temperature ever recorded when Córdoba airport (in southern Spain) hit 116.4 degrees (46.9 Celsius).
In late June, Ahvaz, Iran, soared to 128.7 degrees Fahrenheit (53.7 Celsius) — that country’s all-time hottest temperature.
In late May, the western Pakistani town of Turbat hit 128.3 degrees (53.5 Celsius), tying the all-time highest temperature in that country and the world record temperature for May, according to Weather Underground meteorologist Jeff Masters.
The Capital Weather Gang’s Jason Samenow contributed to this report.