Whether it's hot, cold, or somewhere in between there's one piece of gear that's as versatile as the thru-hiker wearing it- that's a Buff!
Seemingly an overpriced, $30 piece of fabric the buff outweighs and outlasts any handkerchief, or small towel. They come in a plethora of colors and patterns that go from new-age designs to old flannel patterns. The key to this product is its shape and the many ways of wearability.
For cold weather pursuits I recommend the merino wool buff. It's about three times the length of the typical synthetic Buff and has the warming power of wool. Buff's merino wool's quality is a bit lower than others, but it's still worth the price. Wear it as a scarf, balaclava, or a hat liner. It adds warmth and dries quickly. The shape makes it easy to change forms while walking, so enjoy the product in its various forms with ease.
For warmer weather adventures the synthetic version works well. I do not like how much smaller it is, about half the size of the merino wool type, but it is lighter! When you purchase a pattern type it is only printed on one side. This is a problem if you are wearing it around your neck because the non-print side tends to roll out, leaving a chinsy looking product.
However, having a cold, wet Buff around your neck while hiking in the heat feels amazing! I strongly recommend one for any warm weather hiking. Talk about being cooler. Every time the back side gets too warm, just spin the Buff around and the cool front will transfer to the artery on the back of your neck to keep you a few degrees cooler.
Besides keeping the sweat off your back the Buff also provides varying degrees of sun protection. The sun protection, coolmax Buff blocks a whopping 95% of UV rays! Not a bad way to avoid a red neck.
At first glance the Buff may seem like an inflated $30 piece of fabric. Granted it could be about ten dollars less, it is a wise investment. This product has caught on, so look for better, or cheaper versions from other companies this winter!