Mount Everest Precipitation: Low Rainfall, High Variability

Climate of the World's Highest Peak

Mount Everest receives very little liquid precipitation—approximately 380 mm (15 inches) annually—but this metric is misleading for several reasons.

Precipitation Reality

• Mostly snow: At 8,848 m, nearly all precipitation falls as snow/ice
• Measurement difficulty: Extreme wind, sublimation, gauge undercatch
• Spatial variability: Windward (south) vs. leeward (north) differences huge
• Seasonal: Monsoon (Jun–Sep) = 70–80% of annual; winter = minimal

Why "Rainy Days" Is the Wrong Metric

• Liquid rain essentially never occurs at summit
• Snowfall frequency ≠ "rainy days"
• Weather stations rare above 7,000 m; data from Base Camp (5,364 m) or models

Base Camp (South Side) Climate

• Annual precip: ~450 mm (mostly summer snow)
• Precipitation days: ~80–100 days/year (snowfall events)
• Monsoon: Daily afternoon snowstorms Jun–Sep
• Winter: Clear, extremely cold, windy; occasional snow

Climbing Implications

• Pre-monsoon (Apr–May): Best window — stable, cold, low precip
• Post-monsoon (Sep–Oct): Second window — colder, more snow
• Monsoon: Dangerous — heavy snow, avalanches, poor visibility
• Winter: Extreme cold, hurricane-force winds, minimal attempts

Everest's "dry" statistic masks a dynamic snow climate driven by monsoon and jet stream interactions.