Earth’s hottest reliably measured air temperature was 56.7°C (134°F), recorded at Furnace Creek Ranch in Death Valley, California, USA on 10 July 1913. This observation is recognized by the World Meteorological Organization as the highest air temperature ever measured at standard height (1.2–2 meters) in a Stevenson screen, pending modern verification. This evergreen explainer clarifies how such extremes are documented, why confidence varies across historic reports, and how this record compares with other notable hot extremes worldwide.
How Official Temperature Records Work
National meteorological services and international bodies establish official extreme records through standardized observation practices and rigorous quality control. Key steps include:
- Instrumentation and placement: Air temperature must be measured in a properly ventilated Stevenson screen to minimize ground influence.
- Timing and rounding: Values are reported to one decimal in most modern datasets; historical whole-number readings are preserved as recorded but interpreted with context.
- Metadata and chain of custody: Station logs, instrument changes, and observer documentation are retained to assess accuracy over time.
- Review and certification: Expert committees evaluate evidence before endorsing a record as official.
The 1913 Death Valley Record in Detail
On 10 July 1913, a maximum shade temperature of 56.7°C was reported at the United States Army Camp, later the site of Furnace Creek Ranch in Death Valley, California. The reading was taken in a standard shelter and documented in the station log. This measurement held the global highest-air-temperature record for more than a century and remains the benchmark recognized by major meteorological authorities when evaluating historic extremes. Modern reanalysis and cross-checks of available metadata support the plausibility of the event during a multi-day regional heatwave.
Global Context: Other Notable Hot Extremes
Several other locations have reported extreme temperatures, though each requires careful scrutiny of instrumentation, exposure, and measurement practices before being treated as equivalent to an internationally certified air temperature record.
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Death Valley 1913 (56.7°C) | WMO-recognized air temperature at 1.2–2 m; 10 July 1913 | Official station log and WMO assessment |
| El Azizia, Libya 1922 (58°C) | Former record, later invalidated due to instrumentation and exposure issues; not recognized by WMO | Historical station data and WMO review |
| Tirat Tzvi, Israel 1942 (54°C) | Reported shade temperature; among the highest in the Eastern Hemisphere outside Death Valley | Meteorological logs and regional summaries |
| Mitribah, Kuwait 2016 (54°C) | Reliable modern measurement in Asia recognized by WMO as highest temperature in Asia | WMO-certified measurement and peer review |
| Sonchu, Iran 2017 (54°C) | Reliable measurement contemporaneous with Mitribah, confirms extreme regional heat | Operational data and analysis |
| Temperature in Death Valley 2020 (54.4°C to 55°C) | Potential reading on 16 August; under review for possible highest reliable modern measurement | Ongoing WMO review and instrumental analysis |
What Makes a Measurement Official
An official temperature record requires traceable instruments, documented calibration, and observation at regulatory heights in an environment that minimizes local distortion. Readings from non-standard equipment, vehicle roofs, or non-representative locations are typically excluded from record consideration. Observer notes, station relocations, and changes in instrumentation are all factored into assessing long-term reliability. Recent measurements using modern digital sensors benefit from detailed metadata, enabling stronger uncertainty quantification than early twentieth-century paper records.
Common Misconceptions and Why They Matter
Reported extremes often include surface temperatures, satellite retrievals, or values recorded under non-standard conditions that differ from the canonical air temperature record. Surface materials can exceed air temperatures by tens of degrees, leading to confusion when imagery or anecdotes are cited. Validating a record involves examining station metadata, instrument type, exposure, and corroborating data from nearby sites. Clear standards prevent conflating different measurement practices and ensure that historical comparisons remain scientifically meaningful.
Satellite and Remote Sensing Observations
Satellites measure brightness temperatures from the atmosphere or land surface skin and are not equivalent to surface air temperature recorded in situ. While invaluable for monitoring heatwaves and large-scale patterns, satellite retrievals require careful calibration and are not used to establish official surface temperature records. Reanalysis products blend observations with model outputs to provide consistent gridded datasets useful for research, but they do not override site-specific certified measurements used for official extremes.
How Records Are Assessed and Updated
WMO committees periodically review historic claims using published evaluation guidelines. When new evidence emerges, such as digitized logs or improved metadata, assessments can change. For example, the El Azizia record was invalidated after a thorough review, reinforcing the importance of transparent methods. Modern candidates, including Death Valley readings from 2020 onward, undergo similar scrutiny to confirm sensor accuracy, exposure, and data continuity before recognition.
Practical Implications for Travelers and Planners
Extreme heat records underscore the importance of robust infrastructure, early warning systems, and adaptive planning. Designing for worst-case scenarios, incorporating conservative assumptions in engineering, and preparing public health responses can reduce risk during unprecedented events. Understanding how these records are verified helps communicators present credible information to communities facing heat risk.
Key Comparisons at a Glance
- Highest WMO-recognized air temperature: 56.7°C at Furnace Creek, Death Valley, 10 July 1913.
- Notable WMO-recognized modern record in Asia: 54°C at Mitribah, Kuwait, and Sonchu, Iran (June 2017).
- Potential candidate under review: Death Valley, 54.4–55°C on 16 August 2020.
- Former record (now invalidated): 58°C at El Azizia, Libya, 13 September 1922.