The weather will be the biggest factor impacting what clothes you decide to bring. As a South bounder (Maine to Georgia), I hiked in blistering 100-degree August days and slept in snowy 0-degree December nights. Keep in mind this journey will take around 5 months so you can add or remove clothing items as the weather's demands evolve. Let's discuss some pros and cons of materials first and then break down what backpacking clothes I wear.
Layering. Ensuring each layer performs it's intended function adequately can be crucial to a comfortable (and safe) hike.
1) Base Layer - the clothing closest to and touching your body designed to trap your body heat (shirt).
2) Mid Layer - the second layer designed to insulate your body (jacket/ fleece).
3) Outer Layer - the exposed layer shielding you from rain and wind (rain jacket/ shell).
Wool Material. Warm and insulates when wet. It is also fairly odor resistant which can be a big advantage in the shower-less backcountry. A lot of backpacking clothing is 'Merino' which is a specific type of lamb that produces a finer micron follicle. This finer follicle is considered to produce a more quality clothing material versus regular lambswool.
Synthetic Material. Moisture whicking and fast-drying. Nylon, polyester and polypropylene synthetics are generally more durable and rip resistant than wool. Whether it is raining or you are generating buckets of sweat, the Trail can be wet. Therefore, you want to bring some fast-drying synthetic pieces of clothing.
Activity. Keep in mind when you will be wearing the clothing. I had two sets of clothes - what I hiked in and what I slept in. The hiking clothes were generally synthetics that would get sweaty and need to dry fast. My camp clothes were long sleeve wool to keep me warm as the sun went down.
Why it's important: I hiked with a Buff on my head nearly everyday on the AT. It was light and somewhat elastic making it a comfortable and versatile headband. It kept my greasy hair back, prevented sweat from streaming down my face and blocked all sorts of bugs and debris from falling in my hair. The Buff also doubled as a face mask on mornings I wanted to sleep in. The wool beanie is a important addition to insulate on cooler nights by the fire or sleeping in the tent.
2. Upper Body
Why it's important: Both of my synthetic short-sleeve shirts are from Walmart. I would generally wear each shirt for 2 or 3 days of hiking until the next trail town. My clean and dry long sleeve shirt would only be worn at camp once I was done hiking and sweating for the day. I used Arcteryx for my rainshell. While it was helpful to have such a durable 'shield' of a shell, I think a simpler and lighter rain jacket would be just as good. A poncho also doubles as a pack cover.
3. Lower Body
Why it's important: Hiking pants can use thick and heavy fabric and be loaded with pockets and zippers. Instead, I prefer simple and light running shorts with built-in mesh underwear (like a swimsuit). If you are worried about chaffing, feel free to wear underwear (see Exofficio). Same principle as the tshirts - wear each pair of shorts for 2 or 3 days of hiking until the next trail town. Change into your warm long underwear at night at camp.
Why it's important: The classic debate of "trail runners or hiking boots?". Boots are more durable and supportive. Trail runners are lightweight, breathable and dry fast. I hiked with a sort of half breed (Salewa) for most of the Trail. It worked well and held up to rockiest parts of Pennsylvania. However, I switched to trail runners (Brooks) towards the end and fell in love. Boots kept my feet steamy which created blisters. They were also a nightmare to dry after stepping into mud or hiking in the rain (nearly a daily occurrence). I'll never wear anything close to a boot hiking again. Long live trail runners.
Your camp shoes should be ultralight and completely water resistant. Your socks should be wool. I did use sock liners off and on throughout the Trail depending on how bad my blisters were. When needed, they significantly helped reduce friction. I also used ultralight gaiters to block tiny pebbles and pine needles from wiggling into my shoes.
5. Winter (additions)
Why it's important: For anything beyond the summer months, you will want more insulation than the base clothes listed above. Some will be additions, others substitutions.
You will need to add a thick mid layer to provide the majority of your insulation. I recommend a down fill above 700. Gloves were crucial to keep my hands warm while holding my cold metal trekking poles. I even added glove liners for extra protection in snow.
I substituted my lightweight long sleeve (base layer camp shirt) from above for a heavy weight wool long sleeve in winter. The running shorts were substituted as well. Long hiking pants were needed. The zip off option was nice for flexibility in case the sun came out.
By Chris Cage
Chris launched Greenbelly Meals in 2014 after thru-hiking the Appalachian Trail for 6 months. Since then, Greenbelly has been written up by everyone from Backpacker Magazine and Bicycling Magazine to Fast Company and Science Alert. He recently wrote How to Hike the Appalachian Trail and currently works from his laptop all over the globe.