Direct Answer to the Question
The highest reliably measured air temperature on Earth was 56.7°C (134°F) recorded on 10 July 1913 at Greenland Ranch (Furnace Creek) in Death Valley, California, USA. This record is recognized by the World Meteorological Organization (WMO) after a formal assessment that addressed past uncertainties in older measurements. Other extreme values, including unverified claims and satellite-measured land surface temperatures, exist, but the 1913 Death Valley reading is the benchmark for measured air temperature at Earth’s surface.
How Official Temperature Records Are Established
Official temperature records rely on standardized instrumentation, strict siting rules, and rigorous validation. Key elements include:
- Instrumentation: Use of well‑screened Stevenson screens and calibrated thermometers (historically mercury, later digital).
- Environment: Stations placed away from urban heat, reflective surfaces, and direct solar influence.
- Verification: Data are checked for consistency, equipment changes, and anomalies before publication.
- Archiving: Long‑term metadata and digital records support reanalysis when methods evolve.
Together, these practices ensure that extreme values are credible and comparable across decades.
Notable Verified Temperature Extremes
The table below compares verified air‑temperature records and their contexts. Satellite‑derived skin temperatures are noted separately because they measure the ground or cloud top rather than the air near a standard 1.2–2 m height.
| Metric | Value | Date or Period | Location | Source Type |
|---|---|---|---|---|
| Highest verified air temperature | 56.7°C (134°F) | 10 July 1913 | Greenland Ranch (Furnace Creek), Death Valley, California, USA | WMO-recognized station record |
| Lowest verified air temperature | −89.2°C (−128.6°F) | 21 July 1983 | Vostok Station, Antarctica | WMO-recognized station record |
| Warmest decade on record | 2011–2020 | Instrumental average | Global | Multiple agency reanalyses (NASA GISS, NOAA NCEI, Berkeley Earth) |
| Satellite-measured land skin temperature (non-air) | ~70.7°C recorded in Iran, 2005 | 15 July 2005 | Land surface, satellite observation | Satellite observation, not an air thermometer at 1.2–2 m |
Why the 1913 Death Valley Record Is Treated as an Extremum
The 56.7°C measurement at Greenland Ranch passed a modern WMO review that evaluated original logs, equipment, and station conditions. Earlier claims, including a 1922 reading of 58°C in Libya, were invalidated after metadata inconsistencies and poor siting were identified. The Death Valley site, while in a desert landscape known for radiative heating, met siting criteria at the time and produced consistent readings with neighboring, well‑maintained stations.
Seasonal and Geographic Context for Extreme Heat
Continental interiors away from moderating oceans, low elevations below mountain rain shadows, and clear, dry skies in summer create the most intense hot-season conditions. Death Valley lies below sea level and is sheltered by mountain ranges, allowing heat to build. In the Southern Hemisphere, comparable environments are rare, and verified records are correspondingly lower, though extreme values can still occur during regional heatwaves.
How Climate Change Influences the Likelihood of New Extremes
Warming baseline temperatures increase the probability of severe heatwaves and higher records, but declaring a new single-day maximum requires verified measurements and transparent metadata. Changes in instrumentation, observation frequency, and data processing mean that a modern value could only be confirmed if it meets the same rigorous standards applied to historical records. Regional increases in both the frequency and intensity of hot extremes are well documented in multi-decade reanalyses and long-term station datasets.