Temperature at the Summit of Mount Everest: Daytime Extremes

How Cold Is the Roof of the World?

Daytime temperatures at Everest's summit (8,848 m) are **brutally cold year-round**, varying by season and weather systems.

Typical Daytime Ranges

• Pre-Monsoon (April–May) — Climbing Season: **-15°C to -25°C (5°F to -13°F)**. With wind chill: **-30°C to -40°C (-22°F to -40°F)**.
• Post-Monsoon (Sept–Oct): Similar or slightly colder.
• Winter (Nov–Mar): **-30°C to -40°C (-22°F to -40°F)**; wind chill **-50°C to -60°C (-58°F to -76°F)**.
• Monsoon (June–Aug): Warmer (-10°C to -20°C) but heavy snow, high avalanche risk, near-zero visibility.

Record Extremes

• Lowest Recorded: **-62.8°C (-81°F)** (Feb 1, 1999, via satellite/weather station).
• Wind Chill Record: Estimated **-70°C to -80°C (-94°F to -112°F)** during winter storms with 100+ mph jet stream winds.

Physiological Reality

• At 1/3 sea-level pressure, **exposed skin freezes in minutes**.
• Supplemental oxygen mandatory above 7,000 m for most.
• Core temp drops rapidly without exertion; frostbite risk extreme.

Why It Matters

These temperatures dictate climbing windows, gear specs (8000m suits, mitts, heated boots), and turnaround decisions. "Daytime" offers only marginally less lethal cold than night.