Unless you’re an avid outdoorsman who regularly makes hiking, backpacking, or skiing trips outdoors in wintertime, it’s likely that you haven’t given much thought to staying warm in winter. For most of us, we’ll throw on a heavy coat and head straight to the car, relying on the car’s heat to keep us warm. Then we’ll drive to the store and rely on the store’s heat to keep us warm. The only time we’re exposed to cold is the few minutes we’re outside the car.
But have you ever given thought to how to stay warm if your car breaks down and you’re stuck for hours outside in the cold? Or have you ever given thought to how to stay warm if you spend hours outdoors?
Most people try to minimize their time outdoors when temperatures drop, but that isn’t always possible. And if you find yourself unexpectedly outside during cold weather, or if you plan to make excursions outside when it’s cold, you’ll need to prepare accordingly.
How Your Body Loses Heat
There are five primary ways your body loses heat.
- Respiration – breathing in cold air and exhaling hot air.
- Radiation – heat lost from parts of your body exposed to the air.
- Evaporation – heat lost from sweat or water evaporation that cools the body.
- Convection – heat lost through exposure to wind or water carrying heat away from the skin.
- Conduction – losing heat through contact with cooler objects, such as the ground.
In practice, radiation, evaporation, and convection are the three main methods of heat loss which we have to protect against. And the way we do it is by putting on clothing that keeps us from being exposed to the elements, trapping warm air against the body, and remaining dry.
Winter Clothing Materials
The one rule you need to remember when it comes to dressing for winters is “Cotton Kills.”
Cotton is incredibly absorbent and can retain many times its own weight in moisture. If you get sweaty or wet in cotton clothing in wintertime, that moisture will evaporate and the evaporative effect could cause hypothermia and kill you. Cotton’s evaporative cooling is welcome in summertime, but in wintertime it could be fatal.
That’s difficult for many people, as cotton is nearly ubiquitous in every article of clothing today, from underwear to socks to jeans and even flannel shirts. But the dangers of cotton can’t be overstated.
That leaves three primary choices when it comes to choosing clothing to survive in winter: silk, wool, and synthetics.
Recent developments in the production of merino wool have resulted in fabrics that are smooth, lightweight, and comfortable to wear against the body. Merino underwear and base layers can form a good first layer of clothing to keep yourself warm when it gets cold.
Wool clothing has numerous advantages, chief among them the fact that it doesn’t lose its insulating properties when it gets wet. So if you get wet or sweaty in wool clothing, you won’t have to worry as much about hypothermia, as the wool will still be able to keep you warm.
Wool also doesn’t absorb funky odors like cotton and synthetics do, which is ideal if you’re going to be spending lots of time outside. Even after wearing merino base layers for days or weeks they aren’t going to smell bad like cotton clothing can.
And because wool was designed specifically to keep animals warm, it has insulating properties that are second to none when it comes to keeping you warm in winter. The only downside to wool is that it is often expensive, certainly more expensive than the cotton clothing which most of us are used to buying.
Expect to pay $20-30 for underwear, $30-50 for T-shirts, and $50 and up for long base layers. Prices for outer layers will run you even more.
Silk is very similar to wool in its properties, although it won’t keep you as warm as wool and it tends to be very expensive. But silk is lightweight, and is most beneficial when used as a base layer against the skin.
Synthetics come in all different types, with many types of synthetics having been specifically designed to provide warmth in cold weather. Some synthetics can do a good job of keeping you warm relatively cheaply. The primary disadvantage to synthetics is that, being petroleum products, they are flammable, unlike wool.
There are numerous stories of US troops enduring significant and painful skin injuries as their synthetic clothing melted to their skin after IED attacks, leading to synthetic clothing being banned in certain areas of operation. If you expect to be exposed to flames or fire, this should be something you take into account.
Planning Your Layering
We’re all familiar with layering to some extent, as we do it all the time. Underwear, outer clothing, jacket, nice and easy. But in wintertime it’s not that easy.
If you expect to be out and physically exerting yourself in the winter, you have to make sure that you don’t sweat, so your outer layers have to be removable. But you can’t go without those outer layers once you stop being active, otherwise you might freeze.
You also have to take into account layering when it comes to sizing your clothing. You may wear a size Large undershirt, but if you’re adding another base layer, then a midweight layer, then an outer layer, then a coat, each successive layer will add thickness that might require you to start sizing up when you get to the outer layers.
Just remember that while it’s possible to remove layers that you’re already wearing, you’re not going to be able to add layers once you’re out in the wild, so make sure you’re wearing enough to begin with. And be sure to wear enough layers that you can remain comfortably warm and not sweaty no matter the temperature.
It can get warm out in the sun during wintertime, which could lead you to wear fewer layers than you actually need. You might not find that out until you get into the shade, or until the sun goes down and you’re suddenly colder than you expected. Remember, Mother Nature can be a cruel and harsh mistress. If you want to survive in wintertime, you need to plan ahead and make sure that you’re properly dressed and prepared, otherwise your next trip into the cold could be your last.