The question of which country experiences the hottest temperatures involves two distinct measures of heat: the highest single temperature ever recorded and the highest year-round average temperature. The official record for a single event belongs to one country, but a different set of nations endures the most relentlessly hot conditions over the long term. Understanding the difference between these two metrics is necessary to identify the “hottest” country in the world.
How Extreme Temperature is Measured
The World Meteorological Organization (WMO) maintains the official archive of global weather and climate extremes, applying strict criteria for any temperature record to be validated. The standard measurement for air temperature must be taken at a height of 1.5 meters (about five feet) above the ground. The thermometer must be housed in a white, ventilated enclosure, such as a Stevenson screen, which shields the sensor from direct solar radiation and terrestrial heat. This ensures the measurement reflects the air temperature rather than the superheated ground surface.
Ground temperatures can be significantly higher, sometimes exceeding the air temperature by 30 to 50 degrees Celsius, but these are not recognized as official air temperature records. The WMO’s rigorous verification process can take years, involving expert panels that scrutinize the instrumentation, calibration, and observation environment. This meticulous approach is what separates a single, unverified reading from a scientifically recognized extreme.
Heat is quantified in two ways: the absolute maximum temperature and the annual average temperature. The absolute maximum is a single, momentary peak reading that represents an extreme weather event. The annual average is a climate statistic, calculated by averaging daily high and low temperatures over a full year, providing a measure of a country’s baseline thermal environment. The country holding the absolute maximum record is typically not the same as the countries with the highest annual average.
The Country Holding the Maximum Heat Record
The country that officially holds the record for the highest validated air temperature ever recorded is the United States. The record temperature of 56.7 °C (134 °F) was measured on July 10, 1913, at Furnace Creek Ranch in Death Valley, California. This reading has been recognized by the WMO as the highest air temperature recorded on Earth. The location, situated far below sea level in the Mojave Desert, is uniquely positioned for extreme heat accumulation.
The validation of this 1913 record is not without controversy, as some meteorologists question the reliability of the instrumentation used over a century ago. A previously accepted record of 57.8 °C set in El Azizia, Libya, in 1922 was officially debunked by the WMO in 2012 due to recording errors. If the 1913 Death Valley record were overturned, the highest reliably measured air temperature would be 54.0 °C (129.2 °F), recorded multiple times in Death Valley, California, and at Mitribah, Kuwait, in 2016.
Why These Locations Reach Extreme Temperatures
Extraordinary temperatures in places like Death Valley result from a specific combination of meteorological and geographical factors. A primary driver is the low elevation, which in Death Valley is 86 meters (282 feet) below sea level. Air descending into such a deep basin is subjected to adiabatic heating, a process where air is compressed by atmospheric pressure, causing its temperature to rise significantly. The air warms at a rate of approximately 10 °C for every 1,000 meters it descends.
The extreme aridity and lack of vegetation in these desert regions also play a significant role. With no moisture to evaporate and no plant cover to provide shade, solar energy is absorbed directly by the dark, rocky ground. This heat then radiates back into the air, further contributing to the air temperature. High-pressure systems often settle over these regions, acting like a dome that suppresses cloud formation and causes the air to sink, which reinforces the adiabatic heating effect and traps the heat near the surface.
Countries with the Highest Annual Average Temperatures
While the United States holds the record for the highest absolute temperature, countries in the Sahel region of Africa consistently experience the highest annual average temperatures. These countries are located close to the equator and maintain high temperatures year-round, rather than experiencing a single, isolated peak event. Burkina Faso frequently appears at the top of these lists, with an average annual temperature often exceeding 29 °C (84 °F). Mali and Senegal are other nations in this region that endure similar unrelenting heat, with high-pressure systems and a low-latitude position contributing to the sustained thermal environment. These high-average countries are subject to the thermal equator, where the sun’s energy is most consistently intense.