How To Layer Clothing to Keep Warm
Enjoying the mountains to the fullest extent requires knowing how to dress. With the right clothes, an afternoon alpine thunderstorm can make for a surreal and magical experience in the backcountry. But, unprepared, that same storm might leave you recalling a shivering, wicked-cold, misery tour (or worse).

This three-part article is designed to share expert advice and know-how for staying warm in the mountains. We’ll give you an overview of how layering systems work to keep you warm and dry, why you get cold, and our favorite layering systems for different activities and conditions.Here’s an overview of the three articles in this series:
- How to Layer Clothing to Keep Warm – (this article you are reading) Covers how modern technical clothing is designed to work as a layered system and explains each layer from base to outer shell.
- Why You Get Cold in the Mountains – Provides background information on exactly how and why you lose (and gain) heat during outdoor activities, and how a layered system addresses those thermodynamics.
- How to Layer Clothing for Each Season – The part of the series where the rubber meets the road and we provide recommended layered clothing combinations for practical situations ranging from an all-day hike in the mountains to extreme mountaineering.
In this section you are reading we’ll focus on how modern technical clothing is designed to be used as a layered system: each layer serving a purpose in keeping you warm, allowing you to combine different layers to tackle different conditions with grace and style. While layers play a less critical role when car camping, when you engage in athletic exercise, whether it’s hiking, skiing, or climbing, a layered system provides you to the tools to avoid overheating when you are working hard, and yet stay warm when you stop.
Types of Layers
Below we list the different types of layers, which can be used in combination with each other to reach the ideal effect for the season, environment, and activity you are pursuing. These layers work together to achieve the four goals of wicking moisture, trapping in heat, insulating from cold, and blocking wind and weather.
Today, increasing numbers of outdoor-savvy people choose wool over synthetics for their base layer. Why? Many feel that wool insulates better than synthetic base layers when it’s cold, and stays more comfortable over a larger temperature gradient when its hot. Although wool takes longer to dry than synthetics, it continues to insulate well even when wet. Today, wool base layers are made primarily out of merino wool, which is thin and lightweight, less itchy than traditional wool, and does not retain stench. Here at OutdoorGearLab, the Editors prefer wool base layers for most activities. However, we do notice that wool tears and abrades much more easily when rubbed against a rough surface, a key advantage of synthetics for activities such as rock climbing. For activities such as hiking, wool base layers work wonders.
Base layers come in different weights, so depending on the conditions you expect to be in you may select a thicker, more insulating base layer. However, you may be surprised to learn that most mountaineers prefer thin base layers. The reason is that when performing strenuous activities, even in cold environments, overheating can be as big a problem as keeping warm. If you plan on being in cold conditions but also plan on aerobic activity, such as in mountaineering or nordic skiing, typically a thinner base layer is the wisest choice because it helps wick the sweat the best when you are working hard. Rely on the layers above your base layer for insulation. Your base layer’s key function is to manage the conditions right next to your skin.
Lastly, we prefer a zip-neck base layer, which gives you another tool to conveniently regulate body temperature. Alpine activities such as hiking, climbing, or backcountry skiing can seem like an endless cycle of putting on and taking off clothing. A zippered neck can often save you the time required to stop and shed an outer layer. The additional cooling of an open neck is substantial when you are working hard, and easy to zip up when you take a rest.





