Everest is truly a mountain of extremes. Not only does it get very cold, it gets really hot, the air gets really thin and it also gets very windy.
Mount Everest can be extremely cold. The lowest temperature measured on the summit of Everest was in February 2003 with a -41.8°F (-41°C) reading. And the lowest it gets is probably around -76°F (-60°C). But no climber could survive that temperature for long.
The weather can also be quite mild on the summit. On May 27, 2006, Lakpa Tharke Sherpa got to the summit of Mount Everest, took off all of his clothes and stood naked for three minutes in an attempt to set a world record. (source: NBC News).
This didn’t go down well with some of his fellow Sherpas, who thought he had defiled the summit. But he proved that it’s not always cold up there.
How Cold is It on Mount Everest?
Everest’s temperature depends on where you’re standing: from as low as -76°F (-60°C) on the summit to as high as + 95°F (+35°C) in a tent in one of the lower camps. It varies with altitude and season (source: wikipedia).
South Base Camp is located in Nepal at an altitude of 5,364m and varies from a mean daily minimum of minus 19 degrees Celcius in January to a mean daily maximum of plus 11 degrees Celcius in August.
North Base Camp is located in Tibet at 5,5150m, a little higher but not surrounded by ice. Instead it is placed on a dry, windy plateau and the temperature is therefore more dependent on the wind chill. Expect the daily temperatures to be even more extreme than the South Base Camp.
I’ve written more about the temperatures at various camps (and the summit) below.
It might surprise you to learn that sunburn can a problem on Mount Everest: on one of my nine expeditions to the mountain I was panting up a snow slope in fierce sunlight. Unwisely I had my mouth open, and suffered bad sunburn to the roof of my mouth from the reflected sunlight bouncing off the snow in front of me!
On the same expedition, I hung a pair of wet socks out to dry on a washing line between tents. Later I noticed that one sock was steaming in the sunshine, and one was frozen solid in the shadow. And one morning I started to climb at Base Camp at -4°F (-20°C) and ended the day lying in the sun-baked tents at Camp 2 in + 95°F (+35°C).
How Cold is The Top of Mount Everest (Summit)?
It can get as cold as -60°C on top of Everest’s summit. But the weather can also be quite mild on the summit, as Lakpa Tharke Sherpa demonstrated when he took off his clothes.
The winds are a problem for climbers. Winds can get up to 177 mph (285 km/h). The peak of Mount Everest extends into the upper troposphere and penetrates the stratosphere, which can expose it to the fast and freezing winds of the jet stream.
In February 2004, the wind speed of 280 km/h (175 mph) was recorded at the summit and winds over 160 km/h (100 mph) are commonplace. In 1990 I heard a climber complain he was knocked off his feet on the ropes up the North Ridge and blown up the route for 100 feet! (on the Mount Everest Earth Day 20 Peace Climb Expedition).
And another climber was in a tent one windy night when it started being blown down an ice slope towards a cliff. He managed to plunge his ice axe through the groundsheet and self arrested his tent, his gear and himself.
How Cold is Everest Base Camp?
There are two Everest Base Camps, one on the northern, Tibetan side, and one on the southern, Nepali side. This is the one most people talk about trekking to.
In Spring: from April to May, Everest’s North Base Camp is still cold, with temperatures ranging from -10 ° C to 0 ° C, but mostly below freezing.
Summer: from May to September the temperature difference between morning and night is greater. The weather is cool during the daytime, and cold at night.The temperature difference is around 20 degrees Celsius during the day. The lowest is 5 ℃ and the highest is 23 ℃.
Autumn: from October to November, the temperature difference between morning and evening decreases, but the overall temperature drops, and it is dry and less snowy after the monsoon. The temperature is about 6 ℃ ~ 14 ℃. I summitted on October 6th and it was getting noticeably colder every day.
Winter: from January to March freezing and snowfall descend on base camp. The temperature is around -22 ℃ ~ -5 ℃.
Temperatures at the Nepali South Base Camp are similar, although there is more shelter from the wind and the air is somewhat damper due to the wet monsoony air coming from the Bay of Bengal.
At the North Base Camp it is windier and drier due to the rain shadow effect, where the Himalayan chain blocks the moist air coming from the south.
Overall, Everest is both hotter and colder than you might think!