There is a well-known quote by an unknown backpacker that says: “There is no such thing as bad weather, only unsuitable clothing.” This person couldn’t be more right. As a backpacker, we encounter varying weather conditions all the time; especially when making rapid elevation changes. Daytime hiking weather could be in the 70’s or 80’s only to have the nighttime temperature drop near the freezing mark.
For this reason, it’s important to dress appropriately for your trip and to understand the weather conditions likely to be encountered throughout different legs of the journey.
Before getting into how to dress for various weather conditions, it’s important to understand how the body loses heat. Hypothermia can set in quickly as can heat exhaustion if we don’t carefully control the heat of our own bodies.
The four ways our bodies lose heat are:
- Convection is the transfer of body heat into the air. This is the most common cause of heat loss when backpacking and occurs when the air is colder than our nominal body temperature of 98.6° (which is most of the time). The faster cool air moves across our skin, the faster convection takes away body heat. This means clothing should be windproof.
- Conduction is the transfer of heat from one surface to another. Since air is a poor conductor of heat, the best way to keep warm is to wear fabrics that trap the warm air near the body. Water, on the other hand, is an excellent conductor of heat. When clothes become wet they can quickly suck the heat away from the body. Backpacking clothing should be waterproof while still allowing sweat vapor to escape.
- Evaporation is when body moisture (sweat) is transformed into a vapor resulting in a cooling effect. Clothing should transport this excess moisture away quickly through breathable membranes and vents that can be opened and closed to regulate moisture buildup and temperature as needed.
- Finally, radiation is the transmission of heat between two objects without affecting the space between. This is how the sun warms us and if we aren’t careful we can become overheated. Very little heat is lost by radiation, but wearing tightly woven and smooth clothing blocks most of the effects of radiation anyway.
Weight is an important factor when choosing clothing as is the clothing’s ability to keep us warm and dry. The layer system is a way to accomplish all of this while maintaining ideal body temperature in a variety of conditions.
Instead of wearing one or two thick layers, we can wear three, four or even five layers (especially on the torso) to keep warm and shed some of these layers when it’s warm. Often you will find that you have to add and remove layers multiple times throughout the day to maintain a comfortable temperature.
In its simplest form, a proper layer system consists of a thin inner layer of moisture-wicking material, a slightly thicker mid layer designed to trap warm air (insulation) and a waterproof but breathable outer shell that allows perspiration to pass through while blocking wind and rain. You can also add more mid layer clothing items as needed for especially cold weather. The point is that multiple thin layers of clothing is much better for backpacking than one or two thick layers.
The inner layer is only designed to remove moisture from the skin. Usually, these are synthetic, materials designed to wick moisture away from the body but even these materials can become saturated. The mark of a good inner layer is how quickly it dries out once removed. You do not want to put a damp inner layer near your skin on a brisk morning — it isn’t comfortable or fun.
Midlayers have traditionally been made of cotton or wool but since the introduction of fleece both cotton and wool have all but disappeared from the trails. Fleece is warm, dries quickly and is very light compared to other options. A quality inner layer and fleece mid layer are sufficient to keep you warm in all but the coldest climates (especially when combined with a breathable windproof/ waterproof outer shell).
Since you are just starting out, this should be sufficient clothing to keep you warm and dry. As you become more experienced and attempt winter backpacking trips, a down jacket, thick gloves and a wool hat should be added to your gear collection too.
As far as legwear is concerned, shorts are your best bet for mild weather hiking. They are lightweight, comfortable and usually have pockets useful for storing small items on the trail. As long as your upper body is warm, you might be surprised how comfortable shorts can be even in cool weather. This is mostly true while hiking — you may find your legs cold once you camp for the night.
A lightweight pair of hiking pants is a good idea as they can be slipped over your shorts in camp or when the weather is colder than expected. Jeans are a bad idea because they are heavy, uncomfortable and take forever to dry.
You shouldn’t need a moisture-wicking inner layer for your legs unless you plan to backpack in cold or very wet weather but they are small and light enough that it’s not a bad idea to bring them with you just in case.
Your mom was right
When your mom shouted to you that you needed a hat on because it was cold outside, she wasn’t trying to give you a hard time.
You really do need to wear a hat when you are even slightly cold. As much as 80% of body heat can be lost through the capillaries in the head because they do not constrict when cold like in other parts of the body. Essentially, if your feet are cold, put on a hat. Cold feet is a sign that your body is getting too cold so it is shutting down the blood flow to extremities in an effort to keep your brain and torso full of warm blood.
No matter what the weather, you should also carry at least a lightweight fleece hat just in case the evening temperatures are colder than you expected. Of course, if you plan on backpacking in the winter you want to invest in a heavy-duty wool or fleece hat that is comfortable enough to wear all day.
You should also consider a hat designed to keep the sun off your face and head in extremely hot weather. Even something as simple as a ball cap is better than nothing, but many hikers choose something with a brim that goes all the way around the hat for even protection from the sun’s intense heat. Hats are also a great way to keep a bug net in place — something else you should consider because in some places the bugs can be absolutely relentless.
Proper backpacking clothing dictates that we assess the weather conditions likely to be encountered during the trip and implement the layer system using gear designed for the rigors of the trail.