One piece of gear from my Army winter issue kit proved to be more than mandatory — a thick wool military shirt that turned out to perfect for cold weather hiking. If I hadn’t worn that shirt out I’d still be wearing it. Fortunately there are civilian versions available and if you intend to do any winter hiking or backpacking you should get one. Hiking clothes aren’t like other clothes. Protecting the core of the body gives the best protection against hypothermia, but what works best changes quickly. You don’t start out with a perfect clothing configuration and stick with it all day. A good clothing set gives you options for different types of weather without doubling the weight of your packload.
Hikers take many different approaches to trail clothing, and I’ve seen some extreme examples on the trail. While on a pleasant 13 mile day trip in February in the Ozarks one year, outfitted with a minimal day pack and a breathable jacket, I passed a group of backpackers geared up for a week-long stay in the Himalayas. The people in the pack train all wore heavy insulated boots, down jackets, and watch caps in addition to their high-tech hiking clothing. How that managed to do that without expiring from the heat is still a mystery to me, because the temperature that day hovered around 50 degrees F. But, if you bring the gear along I guess you have to put it somewhere, and since their packs were full they had to wear it.
If it’s a nice winter day you can dress lighter than that and keep some emergency options in the pack in case the weather changes. For longer trips when you have to consider unexpected weather problems, a down jacket might occasionally make sense, but for hiking the old rule of “Wear it Loose and in Layers” works better than depending on one heavily insulated piece of gear.
Most of the warmth you feel on the trail comes from the calories you burn. Even in the winter you’ll vent energy like crazy if you keep a good pace going, and the over-dressed hiker soon gets wet with sweat. In the winter that could be deadly, because eventually you’ll have to stop and then that perspiration continues to wick away the heat, but it doesn’t get replaced. Dressing light enough to stay warm without sweating works well, as long as you have backup layers to put on when you stop moving.
Traveling too light in the winter puts you at risk, since even on a day hike something could happen to strand you in the woods for hours or days. Extreme weather changes could drop temperatures more than 50 degrees in a few hours, and it doesn’t take that much to cause an emergency. A cold rain and a steady wind could send you into hypothermia quickly if you aren’t prepared with adaptable gear.
For winter situations you need a warm long sleeved shirt that stays warm even if it’s wet. Most of us can’t tolerate wool fabric on our bare skin, so a polyester blend makes good sense as the bottom layer. A thermal underwear shirt also works, even though it doesn’t look high-fashion. Wear something light over the top of it to ease the social issues.
Add a wool sweater or light wool jacket if the temperature drops or the wind picks up. Adjusting the exertion level to stay warm without sweating makes that basic combination workable over a wide range of temperatures.
If the wind starts to blow mercilessly a rain jacket makes a huge difference in warmth. Going with a rain jacket as outerwear means you’ll need to buy one large enough to wear over your other gear. You won’t ordinarily switch out your light jacket or wool sweater for the rain gear in the wintertime. Rain ponchos are a great idea for the summer, but in the winter they let in too much cold air to be effective against wind chill.
Gloves do more than prevent heat loss. Gloves keep your fingers at workable temperatures instead of just above frostbite level. If your hands get too cold you can’t tie knots or build fires or operate emergency electronic gear. That can happen even if you’re not hypothermic. Try tying a bowline sometime without using your thumbs and you’ll get the idea.
Hats make a huge difference in comfort level, to the good or the bad side. I’m such a believer in the value of wool that I’ve worn several different types of wool caps from baseball versions to watch caps, and none of them were comfortable. I tolerate wool nearly everywhere else but my head. Watch caps are simple and practical for winter wear, and you can roll most of them down as ski mask protection when it gets really cold.
If you go unprotected up there you can loose most of your heat through the top of your head, but if you overdo the cranium insulation you’ll get into that perspiring mode quickly. An acrylic knit watch cap works best for me in mild weather, and if things get really cold I’ll add a hood from jacket or rain gear. When the weather gets even worse, step up to a Gore-tex watch cap and the warmth of wool without the itch.
A scarf might not be a common piece of hiking equipment but again it’s a piece of Army issue gear that I grew to really appreciate. Instead of a scarf I usually just tie a bandanna around my neck loosely to fill the gap between collar and self on cold days.
That’s the lightest and most adjustable core set of winter clothes I’ve come up with for moderate winter weather, the range from 20 to 50 degrees F. If it’s going to get colder than that it’s time for heavier layers and that down jacket might finally be sensible.