Mount Everest, the world’s highest peak, stands at 8,848 meters (29,029 feet) above sea level. Its summit experiences consistently frigid temperatures. Understanding these temperatures provides insight into the severe conditions mountaineers face.
Typical Summit Temperatures
The summit of Mount Everest remains significantly below freezing throughout the year. During winter, from December to February, the average temperature is around -36°C (-32.8°F). January is typically the coldest month, with average temperatures around -37°C (-35°F).
Even in summer, between June and August, the average temperature ranges from -18°C to -20°C (-0.4°F to -4°F). The warmest recorded temperature was approximately -16°C (3°F). The lowest officially recorded temperature was -41°C (-42°F) in December 2004. Winter temperatures can plunge further, reaching as low as -60°C (-76°F).
These average temperatures are determined through atmospheric models and historical data. Spring, particularly April and May, is the prime climbing season, yet temperatures still range between -20°C and -30°C (-4°F to -22°F).
Factors Contributing to Extreme Cold
Mount Everest’s extreme cold stems from several interconnected scientific principles. Its immense altitude is a primary contributor, as temperatures generally decrease with increasing elevation, a phenomenon known as the lapse rate. For every 1,000 meters ascended, the temperature typically drops by about 6°C. This occurs because the air at higher altitudes is thinner and less dense, meaning there are fewer air molecules to trap and retain heat.
Reduced atmospheric pressure at the summit further exacerbates the cold. As air rises, it expands due to lower pressure, and this expansion causes the air to cool. This process, known as adiabatic expansion, means that even if sunlight is intense, the thin air struggles to hold onto any absorbed heat.
The summit also frequently interacts with the jet stream, a band of fast-moving air high in the atmosphere. For much of the year, particularly from mid-October to early April, hurricane-force winds exceeding 120 km/h (74 mph) batter the summit. These powerful winds rapidly dissipate any heat that might accumulate, preventing the air from warming.
Additionally, the air at such high altitudes tends to be very dry, meaning it contains little moisture. Water vapor is an efficient absorber and re-emitter of heat, so its scarcity reduces the atmosphere’s capacity to retain warmth. While direct solar radiation can be strong due to the thin atmosphere, the overall lack of heat retention by the air ensures that temperatures remain severely low.
The Impact of Perceived Temperature
The actual air temperature at Mount Everest’s summit is only one part of the challenge; the perceived temperature can be significantly colder due to wind chill. Wind chill describes the chilling effect of wind on exposed skin, which accelerates the rate of heat loss from the body. Even if the air temperature is, for example, -30°C, strong winds can make it feel much colder.
With sustained winds often exceeding 100 mph (160 km/h), the wind chill can make the perceived temperature plummet to as low as -70°C (-90°F) or even -83°C (-117°F) in winter. This extreme wind chill rapidly removes heat from any exposed skin, increasing the risk of cold-related injuries. Frostbite, where body tissues freeze, can occur almost instantaneously under such conditions.
The combined effect of extremely low air temperatures and severe wind chill means that the body loses heat at an alarming rate. This rapid heat loss can quickly lead to hypothermia, a dangerous drop in core body temperature, even with appropriate protective gear. Climbers must therefore account for this significantly colder perceived temperature in their preparation and ascent strategies.