Mount Everest, the highest mountain on Earth, stands at an official elevation of 8,848.86 meters (29,032 feet) above sea level, straddling the border between Nepal and the Tibet Autonomous Region of China. Whether the mountain is always snowy depends heavily on the specific altitude and time of year. While the upper reaches are perpetually frozen, the lower slopes experience a distinct seasonal cycle of snow accumulation and melt.
Defining the Permanent Snow Line
The concept of the permanent snow line answers the question of permanent snow cover. This is the altitude threshold where annual snow accumulation exceeds the amount lost to melting and sublimation. This elevation allows glaciers to form and persist year-round. Because Mount Everest is near the Tropic of Cancer, its permanent snow line is among the highest in the world due to intense solar radiation.
In the Himalayas, the permanent snow line typically ranges between 5,500 and 5,700 meters (18,000 to 18,700 feet) above sea level. Below this elevation, snowfall is seasonal and temporary, melting completely during warmer summer months. Above this line, the mountain remains covered by a permanent layer of snow and glacial ice. The lower sections, including Base Camps, often fluctuate between bare ground and snow cover depending on recent weather events.
Seasonal Weather and Snowfall Cycles
The mountain’s visual appearance is governed by three distinct seasonal weather cycles that control the depth and texture of the snowpack. During the pre-monsoon season, the primary window for climbing, the weather is generally drier with less frequent snowfall. Strong winds at high altitudes compact or strip away loose snow, often leaving behind a hard, icy surface and exposing underlying rock.
The monsoon season, running from approximately June through September, brings the heaviest precipitation and is responsible for about 75% of the annual snow accumulation. This influx of moisture results in the deepest, freshest snow cover of the year, making the mountain appear uniformly white. However, the heavy snowfall and increased cloud cover during this period make conditions unstable and unsuitable for climbing.
Following the monsoon and leading into winter, the mountain is subject to the influence of the polar jet stream as it dips south. This brings extremely cold temperatures and high-speed winds that scour the peaks, significantly eroding the fresh snowpack. The fierce winds blow away the loose, powdery snow, causing the mountain to appear less soft and more exposed than immediately after the monsoon.
Extreme Altitude and Ice Composition
Near the summit, the environment is too extreme for fresh, light snow to maintain its form, even though temperatures never rise above freezing. The permanent covering at the highest elevations is a combination of hard ice and exposed rock, not a fluffy snowpack. High-altitude ice in this zone is subject to sublimation, where frozen water transitions directly into water vapor, bypassing the liquid phase entirely.
Sublimation is intensified by strong solar radiation, extremely low humidity, and constant high winds typical of the upper mountain. This constant loss of ice, estimated to be equivalent to decades of accumulation annually, prevents an endless buildup of snow on the peaks. The remaining permanent ice layer is highly compressed and dense glacial ice, sometimes referred to as blue ice, which is ancient and extremely hard.
This dense, permanent ice is often exposed when intense winds strip away the surface snow, revealing the underlying structure. The highest parts of Everest are permanently covered, but this coverage is often hard, blue glacial ice and rock, rather than fresh white powder. The summit is defined by the relentless processes of wind erosion and atmospheric sublimation acting on ancient, compressed ice.