World Meteorological Organization

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World Meteorological Organization

The highest temperature recorded on Earth has been measured in three major ways: air, ground, and via satellite observation. Air measurements are used as the standard measurement due to persistent issues with unreliable ground and satellite readings. Air measurements are noted by the World Meteorological Organization (WMO) and Guinness World Records among others as the standard to be used for determining the official record. The current official highest registered air temperature on Earth is 56.7 °C (134.1 °F), recorded on 10 July 1913 at Furnace Creek Ranch, in Death Valley in the United States.[1] For ninety years, a former record that was measured in Libya had been in place, until it was decertified in 2012 based on evidence that it was an erroneous reading. This finding has since raised questions about the legitimacy of the 1913 record measured in Death Valley, with several meteorological experts asserting that there were similar irregularities. The WMO has stood by the record as official pending any future investigative results. If the current record were to be decertified then the holder would be a tie at 54.0 °C (129.2 °F), recorded both at Furnace Creek and in Kuwait.

Several unverified temperatures that exceed the current record have also been recorded. These include historical claims that were never authenticated due to the equipment available at the time and unverified scientific claims. There are also disproven amateur readings that have been posted on social media showing evidence of extreme temperature.

History

Thermometer reading at Furnace Creek Ranch (July 2005)
The standard measuring conditions for temperature are in the air, 1.5 metres (4 ft 11 in) above the ground, and shielded from direct sunlight.[2] Global surface temperatures as a whole have been monitored since the 1880s when record keeping began.[3] According to the World Meteorological Organization (WMO), the highest registered air temperature on Earth was 56.7 °C (134.1 °F) in Furnace Creek Ranch, California, located in Death Valley in the United States, on 10 July 1913.[1][4][5] This record was surpassed in 1922 by a reading of 57.8 °C (136.0 °F), registered on 13 September 1922, in ʽAziziya, Libya.
Ninety years later, this record was decertified, making the former reading in Death Valley the world's highest official temperature again. The decertification of the former record in Libya has since cast doubt on the validity of the 1913 recording.[6] If the 1913 record were to be decertified, the highest established recorded air temperature on Earth would be 54.0 °C (129.2 °F), also recorded in Death Valley on 20 June 2013, and in Mitribah, Kuwait on 21 July 2016.[7] There have since been higher readings of 54.4 °C (129.9 °F) in August 2020 and July 2021, both at Furnace Creek, that are pending validation.


Measurements have also been taken in two other ways via ground and satellite readings. Temperatures measured directly on the ground may exceed air temperatures by 30 to 50 °C (54 to 90 °F).[12] The theoretical maximum possible ground surface temperature has been estimated to be between 90 and 100 °C (194 and 212 °F) for dry, darkish soils of low thermal conductivity.[13] While there is no highest confirmed ground temperature, a reading of 93.9 °C (201.0 °F) was allegedly recorded in Furnace Creek Ranch on 15 July 1972.[14] Temperature measurements via satellite also tend to capture the occurrence of higher records but, due to complications involving the satellite's altitude loss (a side effect of atmospheric friction), these measurements are often considered less reliable than ground-positioned thermometers.[15] Satellite measurements of ground temperature taken between 2003 and 2009, taken with the MODIS infrared spectroradiometer on the Aqua satellite, found a maximum temperature of 70.7 °C (159.3 °F), which was recorded in 2005 in the Lut Desert, Iran. The Lut Desert was also found to have the highest maximum temperature in 5 of the 7 years measured (2004, 2005, 2006, 2007, and 2009). These measurements reflect averages over a large region and so are lower than the maximum point surface temperature.[