Why You Get Cold in the Mountains

March 31, 2015 How to
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Ever wonder why you get cold in the mountains? Because when moving in the mountains, you have a tendency to sweat which can make you cold. So, staying warm and dry is a major concern. Mountain weather is grossly unpredictable where heavy winds and storms can come quickly.  If you are unprepared with protective and insulating clothing, you can be at serious risk for hypothermia.

Normal body temperature is 36 degrees Celsius, or 98.6 degrees F.  Safe normal body temperature range is only within one degree Celsius – within 36.5 and 37.5 degrees, and less than 2 degrees Fahrenheit – within 97.7 and 99.5 F.  The body has a very narrow safe temperature range.  Go outside of this range, and the consequences can be serious. This is why we have every incentive to stay warm and dry.

There are four ways your body loses heat:

1.  Evaporation

When you’re wet, whether it be from evaporation or precipitation, the process of evaporation cools you off. Everyone knows that we sweat when we get hot, and that is simply because when moisture evaporates, it absorbs heat and we feel cooler. This can be dangerous, however, in an alpine environment because this cooling can happen too quickly, and at a rate which we can’t warm up again.

Mountain weather is unpredictable and subject to sudden weather changes.  The classic mistake is to hike in cotton. Cotton is simply the worst choice because it retains moisture like a sponge, so when you stop exercising and hence stop producing heat, you are wearing the equivalent of a wet towel next to your skin, robbing your of heat.

This clammy, soggy layer next to your skin invites evaporative cooling.   If weather changes for the worst, you are stuck with this layer that does nothing but takes moisture away from your body, putting you at risk.  If there is precipitation the situation becomes serious very fast.

The best layers wick moisture when you are working hard and insulate when you stop.  Merino wool dries quickly but also stays warm when wet, so it is your best option.  The best layering systems manage moisture from the inside by wicking sweat and don’t cause you to overheat when working hard.

Managing Cooling via Evaporation:

Moisture wicking layers, such as those made with merino wool. For example, try Icebreaker or SmartWool. Learn how to choose a base layer.

Staying warm and dry in the mountains with a merino wool base layer.

Staying warm and dry in the mountains with a merino wool base layer.

2.  Radiation

When you’re working hard, your body produces heat.  This heat evaporates, and if too much of it evaporates, it may be hard for your body to keep it’s core temperatures up.  You can get cold fast. To manage this it’s pretty simple – simply dress warm.

A warm jacket to block the wind or elements, and don’t forget – a hat! Most of our heat loss is from our chest and core (where our internal organs are), but this is not true when you’re outside in a cold environment.  Much of the heat loss evaporates from your head. This is why it’s so important to have a good quality hat or toque as well as a comfortable heat trapping mid layer.  To learn how to layer clothing, read our article on how to layer.

Managing Cooling via Radiation: 

Insulating mid layers and a warm hat.

Mike layered up for the cold with a merino wool hat and Patagonia Better Sweater.

Mike layered up for the cold with a merino wool hat and Patagonia Better Sweater.

3.  Conduction

Heat can also be lost when you touch something that is colder than you are. If you backcountry ski, you know that you would never sit on the snow when you’re having a lunch break because it would cool you off very fast. You would instead sit on your backpack or on your skis.

When outside, consider what you might be touching that can make you cold. This is a classic problem for ice climbers, who need very warm and waterproof gloves to keep their hands warm due to touching ice tools, screws and the proximity of the ice.

Warm socks and proper footwear – such as those made with Gore-Tex, to keep your feet dry – are critical in rainy or snowy weather.  Since your feet can get sweaty, proper socks moisture wicking are important – don’t wear cotton socks. We recommend merino wool socks. They stay warm when wet.

If it’s raining or sleeting outside, make sure to have waterproof layers to protect your core and head as wet snow or rain will cause rapid heat loss through conduction.

Managing Cooling via Conduction:  

A waterproof outer layer, good quality socks, and insulating layers.

Now that is some bad weather! Standing on the summit of The President at 10,296 feet (3138 m).

Now that is some bad weather! Standing on the summit of The President at 10,296 feet (3138 m).

4.  Convection

The last way that heat is lost is through convection.  Heat can simply get blown away – this is known as wind chill, when the temperature felt on the body is much colder than the reported ambient temperature. The process of wind chill combines the worst of evaporation and convection.

Convection cools because of movement of air and fluids – we all know that heat travels from hot to cold.  So when a cold gust of wind blows, it will blow your protective heat ‘layer’ away, but also can chill you to the bone by pushing cold air through to your sweaty layers next to your skin.   Cold air, or cold fluids (think rain or snow) cool you like this: they move next to your skin, warm up, and move away, taking your heat with them, allowing more cold air or fluid to take it’s place, and cool you off even more.  The double-cooling method of convection and evaporation is the fastest way to get hypothermia.

You need to stay dry from precipitation and protected from wind.

Managing Cooling via Convection:

Base layers that wick moisture and wind blocking outer layers. Gore-Tex jackets work very well in blocking wind.

Staying warm and protected from the wind at Waterton Lakes National Park.

Staying warm and protected from the wind at Waterton Lakes National Park.

We hope this article has helped explain why you get cold in the mountains, and why it’s important to take every precaution to stay dry and well insulated.

How do you stay warm in the mountains? Enter your comments below!

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