Many of us who have grown up spending vast amounts of time in Mother Nature's playground take for granted the notion of proper layering. We've learned from our parents or grandparents, maybe found out the hard way with a little trial and error, and now have the idea so ingrained in our subconscious that we don't even have to think about it...it's pretty much an automatic action. However, there are plenty of people out there who are just learning a sport...just getting into hiking, just learning to ski, or maybe fishing winter steelhead for the first time ever and understanding proper layering techniques is a daunting task above and beyond simply overcoming the nervousness/excitedness of taking on a new endeavor. I also have plenty of friends who live in the southern U.S. who have a strong grasp of warm-weather activities but who just don't have much experience with cold weather layering. Those friends who come to the mountains of the northwest during the cooler/colder months just don't get enough practical experience in cold weather layering. So, here's a simple, distilled version of proper layering techniques:
Let's run through a typical cool to cold weather layering scenario....
You will usually hear three main categories referenced in regard to layering. Here's a simple chart to help connect the dots...
1. BASE LAYER (soft, thin, close to body. Usually some form of polyester for moisture transport)
2. MID LAYER (loftier, thicker warmth layer. Poly is still the best bet here for moisture transport but merino wool is a great option here too... on severely cold days, add a light, thin down/down alternative sweater/jacket.)
3. OUTER LAYER (your outer defense against wind, rain, snow, etc. Many many options here)
1. BASE LAYER
The base layer refers to the inner-most layer, closest to the skin. This layer is very important in cold weather mainly for its moisture-wicking properties. Yes, it will of course add a thin layer of subtle extra warmth, but removing moisture (most likely sweat, water from the river, snow, rain, etc) is vital in cold weather conditions. If moisture is left in contact with the skin, the combination of wetness and cold air can make the body feel chilled and , worst-case scenario, lead to hypothermia. I would highly suggest staying away from cotton here in lieu of synthetic, polyester-based materials. Thin merino wool is sometimes used here too, however, many people are sensitive to wool...even soft merino. So again, I tend to stick to a polyester-based, thin, somewhat form-fitting, stretchy material.
2. MID LAYER
Your middle layer, 2nd layer, or mid layer is your warmth-added layer. Soft cotton layers are sometimes used here but I still prefer a synthetic material such as a polyester fleece. A poly/cotton blend is fine here too but cotton doesn't transport moisture away from the body as well as synthetic materials do. I don't mind going for a merino wool layer here either. Merino is super soft, keeps insulating even if wet, and has a natural antimicrobial property, meaning you can wear it for days on end in the back-country and it won't smell like a fast food wrapper you left in your car two weeks ago.
Your mid layer should be temperature appropriate. Heavier and thicker for really cold days, and lighter/thinner for days that aren't too chilly (of course you may tolerate cold better than I do or vice versa so your personal tolerance needs to be factored in here as well). On really cold days I will personally have two mid layers...say a thin merino cardigan under a my Fade Pines Fleece Hoodie for more warming protection. On extremely chilly days...consider having your second mid-layer being a thin, light down or down alternative sweater/jacket.
You'll also want to take into consideration your level of activity: winter fishing from a driftboat doesn't include a ton of physical exertion so you may need to have a warmer mid layer or you may want to double up your mid layer. Hiking or running outside will have you building up a ton of heat and sweat so you may not want to have a super thick mid layer...moisture wicking is probably your most important factor in those two activities. Skiing/snowboarding is tricky because the physical exertion will build up lots of heat and moisture, but the chairlift ride will cool you down dramatically. In this situation, I would recommend a warm mid layer (or layers) with high moisture transporting properties (like polyester) with an outer layer (which we'll talk about next) that can easily dump excess heat and humidity.
When I think about winter activities outside, to me, the mid layer is probably the most tricky while being just as important as your outer layer....
3. OUTER LAYER
Your choice in outerwear is a critical one. Outerwear is your first line of defense against the elements and, while you could just go for a strong defense to cover your bases, you'll be most comfortable and therefore get the most enjoyment out of your outdoor activities if your outerwear is matched to the elements.
You'll want to get a good look at the weather forecast to choose an appropriate outer layer (and mid layering choices too), but when it comes to the outdoors, it's best to be over-prepared...meaning I'll pack (but not necessarily wear) some extra layers. On cool, sunny days, an outer layer may not be necessary...your "mid layers" will do the trick. But, add in a little wind and a light jacket with wind-breaking properties will do great. If there's rain in the forecast, well...your jacket best have some great water-shedding/waterproofing properties! You'll pay more for a breathable AND waterproof outer layer (sometimes called a shell or simply/obviously a jacket), but moving that excess heat and sweat out of your jacket while still keeping the rain or snow out is a really big bonus. If it's raining pretty steadily, your shell of choice may be a little more "plasticky" in feel or have a soft crackling sound when moving...which is why if it's not raining heavily but snowing or just sprinkling, you can usually get away with a softer-more pleasant feeling and sounding jacket. While rain jacket materials have gotten more pleasant and higher tech, there are still noticeable differences in feel and in the sound of rain-specific jackets and other jackets.
With an outer layer (shell, jacket, etc.) insulation is really not as important as water/windproof-ness (yes, I am allowed to make up words) and moisture management. Your mid layers are more important for building warmth. So even on a cold day of winter fishing, I may just wear a highly technical wind/rain shell over warm mid layers. However, some people (and in some situations I do this too..) prefer to have a little insulation factor in their outerwear. If you're prone to getting cold easily, this may be a great option for you. Again, you'll want to keep in mind your activity...layering is never the same across the board. If I'm going to go snowshoeing which includes moderate to high levels of physical exertion, I personally wouldn't want to wear an insulated jacket...just a windproof and snow-proof shell for mobility and great protection from blowing cold and moisture. While floating in a driftboat all day, on the other hand, I'm not really building up much excess heat...just standing in place and casting a fly rod. In this situation, I'll opt for a weatherproof and somewhat insulated jacket as my outerwear choice.
Other things to look for in outerwear are convenience features like appropriate pockets (or lack thereof in some cases...bulk isn't conducive to free movement) hoods, and pit zips. Pit zips are a fantastic invention and help quickly dump excess heat and sweat in a timely manner and then are zipped back up to keep the elements out. As stated above, I don't like to over do my outerwear...think of freedom and ease of movement, appropriate atmospheric moisture protection, wind protection, and inner moisture management relative to your activity. If your'e not over exerting yourself and therefore not worried about getting too hot, or you simply get cold easily, pay attention to insulation level.
Just because I don't like to over-dress doesn't mean I don't like being prepared! I tend to bring a light, easy to wear backpack or bag with an extra shell, extra mid layer, and a fresh, dry pair of socks. Even if the forecast is hot and sunny...well...in the mountains where I work, you never know when a thunder storm could roll in on you and drop the temp 20 degrees! I never let friends or clients enter my boat without a rain shell and even suggest a hoodie or polyester long-sleeve mid layer just in case.
The options are many, I know...and can seem daunting sometimes. I hope you've found this quick guide a helpful place to start. Now get out there, play around, and see what works for you!
Feel free to add questions or comments!