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Dr. Tom Matthews and Dr. Baker Perry, members of the National Geographic and Rolex Perpetual Planet Extreme Expedition to Mount Everest, work on the automated weather station at Everest Base Camp. Learn more at

Freddie Wilkinson/National Geographic

What’s it like to install a weather station at the top of the world?

SAN FRANCISCO, CALIFORNIA—Earlier this year, researchers installed the world’s highest weather station on the upper reaches of Mount Everest. The roughly 50-kilogram station, taller than a person, is one of five on and near the mountain that are collecting data about jet steam winds and warming conditions in High Mountain Asia, a region jam-packed with the most glaciers outside of Earth’s poles.  

Tom Matthews, a climate scientist at Loughborough University in the United Kingdom, and Paul Mayewski, a glaciologist at the University of Maine in Orono, were part of the record-setting expedition. Matthews presented some of the group’s results last week here at the annual meeting of the American Geophysical Union. The two researchers chatted with Science about working at extreme altitudes, the power of body heat, and dealing with crowds on one of the world’s most dangerous mountains.

This interview has been edited for clarity and length.

Q: Why put weather stations on Everest?

A night wind spins the anemometer of a newly installed automated weather station in Phortse (3810 meters above sea level). The weather station, installed during National Geographic and Rolex’s 2019 Perpetual Planet Extreme Expedition to Mount Everest, provides real time weather readings from the world's highest mountain. Explore the data at

Eric Daft/National Geographic

Tom Matthews: For starters, it’s high enough that we can monitor the really fast, high-altitude winds known as the Subtropical Jet Stream. These winds have a global impact because they affect how storms move. By working on Everest, we’re also able to study how climate change is affecting High Mountain Asia. There’s an enormous amount of ice sitting very high up, above where we previously had any measurements of the weather. Understanding the conditions in this area is important because High Mountain Asia is the water tower of the world—10 major river basins start here and sustain billions of people.

Q: Where are the weather stations located?

T.M.: One is in the Nepalese village of Phortse, at an elevation of 3810 meters. Another is near Everest base camp at an elevation of 5315 meters. The last three stations are all located along one of Everest’s most popular climbing routes: One is at 6464 meters, one is at 7945 meters, and one is at 8430 meters.

Q: What were some challenges you faced?

T.M.: The cold. It was –24°C at the Balcony, a flat spot about 400 meters below the summit where we placed our highest station. With the wind chill, it felt like –29. It was so cold that the drill we needed to secure the weather stations to the bedrock stopped working. One of our Sherpas stuck it into his suit, and it eventually warmed up from his body heat. That would have been a game stopper. We couldn’t have installed that weather station without the drill.

Paul Mayewski: You’re totally dependent on oxygen at higher elevations. At the top of Everest, the air is a lot thinner than at sea level. Imagine trying to do something relatively complicated with about a third of the oxygen you would normally have. You’re also confined by an oxygen mask, heavy clothing, winds whipping around you, and lots of other people nearby. It’s probably one of the most extreme environments you can think about working in.

Q: This year was particularly crowded on Mount Everest. How did other climbers react to your expedition?

P.M.: We had a big group consisting of Sherpas, climbing guides, scientists, and members of the media. We generally tried to stay out of other people’s way. Everyone who is climbing Everest is in a world of their own. As long as you’re not directly in their way, they might not even notice you. But we noticed the crowds. We were originally hoping to install our highest weather station as close as possible to the summit. But there were about 200 people in line ahead of our team. Even if each person in that line spent only 1 minute at the summit, it was going to take close to the equivalent of one oxygen tank to wait. Our team ended up installing the station a few hundred meters below the summit, but that was the right decision. It was far smarter to be safe.

The high-altitude expedition team drills the world’s highest ice core sample at 8020 meters above sea level during National Geographic and Rolex’s Perpetual Planet Extreme Expedition to Mount Everest in spring 2019. Learn more at

Dirk Collins/National Geographic

Q: Will data from these stations help keep climbers safe?

T.M.: Roughly a quarter of the deaths on Everest can be traced back to bad weather. Climbers traditionally have had to rely on forecasts of Everest’s weather, but those are just predictions based on models. You have no idea if they’re any good. They haven’t been tested. We have the ability to test them for the first time. That means safer climbing.

Q: What have you learned so far?

T.M.: We’ve seen incredibly high values of sunshine. At particular times of the day, it can be more than you’d get at the edge of space. That’s because sunlight is reflecting multiple times off the snow and clouds. Added together, the sum of what’s coming down is more than what’s available at the top of Earth’s atmosphere. That helps explain why climbers regularly suffer from heat exhaustion even through temperatures are well below freezing.

Q: How long will these stations remain in place?

T.M.: In theory, everything could last quite a long time. We’re talking years. The instruments run on batteries, which are charged by solar panels. But high winds have destroyed instruments on Everest in the past. In 2008, rocks blew into an Italian weather station and destroyed it. We have to be realistic. This environment is incredibly extreme. However, most of our stations were designed with pairs of redundant instruments. If one is damaged, the other should carry on.

*Correction, 18 December, 3:45 p.m.: This story was revised to reflect that the wind chill–corrected temperature during the installation of the highest weather station was –29°C, not –39°C.