What −40°C taught us about what 'warm' actually means

Mongolia has one of the most extreme climates in the world. In extreme cases, the temperature has been recorded going as high as +44°C during the summer of 1999 and as low as -55.3°C during the winter of 1976, which makes for a nearly 100°C recorded temperature range. In a country as cold as ours, being warm isn't just a luxury, it's a necessity.
Mongolians have been living in this climate for thousands of years, and so have the animals that live alongside us. Over thousands of years, people learned how to live with the cold, the heat, the wind and the dry conditions of the steppe. Animals adapted to these conditions too. One of the best examples is the yak, an animal that is exceptionally well suited to life in cold, high-altitude environments.
Yaks are one of the reasons Mongolian people have been able to live in such an extreme climate for so long. They provide milk, meat and, perhaps most importantly for us, fibre that can be turned into clothing and other useful materials.
So what actually makes something warm?
When we talk about warm clothing, it is easy to think that the material itself somehow creates heat. It doesn't. Your body creates the heat. Good insulation helps stop that heat from escaping. A large part of this comes down to air.
Fibres create thousands of tiny spaces that can trap air. Air is a relatively poor conductor of heat, so these pockets slow down the movement of heat from your body to the colder environment around you. The structure, thickness and density of a fabric all affect how well it can do this.
This is one of the reasons natural animal fibres have been useful for clothing for thousands of years. Their structures are not random. They have developed to protect animals from the environments they live in. And this is where the yak becomes particularly interesting.
The yak's natural insulation
A yak's coat is made up of different types of hair. The longer, coarser outer hairs help protect the animal from wind, snow and the elements, while the fine undercoat provides much of its insulation.
Research into yak fibre has found that the fine fibres have a naturally crimped structure. This helps create spaces within the fibre mass where air can become trapped, contributing to its insulating properties.
In other words, the yak doesn't need to be told how to survive a Mongolian winter. Its coat has been doing the job for a very long time. When we take that fibre and turn it into clothing, we are not inventing a new way of staying warm. We are making use of something that nature has already spent a very long time developing.
But cold isn't the only challenge
Mongolia isn't simply a place where it gets very cold.
Our climate can swing from extremely cold winters to very hot summers. The country has a strongly continental climate, meaning there is little influence from the ocean to moderate temperatures. This contributes to the huge differences between summer and winter temperatures. That means clothing has to do more than simply block out cold. Comfort matters too.
Natural fibres such as wool can absorb moisture vapour from the surrounding environment. Wool is known to be hygroscopic, meaning it can take up moisture without immediately feeling wet. This is one of the properties that contributes to the way wool garments handle changes in temperature and humidity.
Of course, warmth is never determined by the fibre alone. How a fibre is spun, how tightly it is knitted or woven, the thickness of the garment, how it fits and how it is layered all make a difference. There is no single number that can tell you exactly how warm a sweater will be.
Thousands of years of living with the land
People in Mongolia have been living with these conditions for thousands of years. Archaeological evidence shows that pastoral communities were already keeping livestock and consuming dairy in Mongolia around 5,000 years ago.
Over generations, livestock became much more than a source of food. Animals provided materials for clothing, shelter, transportation and everyday life. People learned to work with what the land could provide and to make use of animals that could survive where other livestock would struggle. The yak is a particularly good example of this relationship.
Yaks are naturally suited to cold, high-altitude environments. Their thick coats allow them to withstand conditions that would be difficult for many other animals. For the people who live alongside them, that natural protection has become a valuable resource. Today, we can take the fibre from that same environment and turn it into modern clothing without losing the connection to where it came from.
So what did -40°C teach us?
It taught us that warmth isn't really about a number on a thermometer. It's about holding onto the heat your body already produces. It's about insulation, fibre structure, moisture, wind and the way a garment is made. And in Mongolia, we have had a very long time to learn about all of those things.
For thousands of years, people here have lived through some of the most extreme temperatures on Earth. The animals around us have adapted to the same conditions, and we have learned how to make use of what they provide. Yak fibre is one small part of that much bigger story. For us, making yak clothing isn't just about finding a soft or luxurious material. It is about taking something that comes from the Mongolian landscape, turning it into something useful and beautiful, and keeping that connection to the land along the way.
Because when you come from a place where -40°C is a reality, you learn pretty quickly what warm really means.