Q. My outdoor activities tend to be in the fall and winter months. With all the new fabrics and materials coming to market in the past few years, I really do not know what direction to turn for 2nd layering. In the past I have just stuck with named leaders. It is time to update my clothing, and the 2nd layer is the unknown. Will you help me by explaining some of the differences and what, in your opinion, a person should look for in this important clothing layer?

A. That's a tough question to answer. You're right, there have been a proliferation of high-tech fabrics, and these days there's a specific garment for virtually every kind of activity. So it really depends on what you're doing outdoors, and in what temperatures.

Here are some basic guidelines:
1. The colder the temperature, the thicker the 2nd layer.
2. The warmer the temperature, the thinner the 2nd layer.
3. The more aerobic the activity, the thinner the 2nd layer.
4. The more sedentary the activity, the thicker the 2nd layer.

So with that I will suggest some pieces for each rule above:

1. Go with a 200-300 weight fleece in cold temperatures:
The North Face Pumori
The North Face Denali Jacket
Mountain Hardwear Monkey Man Jacket
If these are too warm, try a 100 weight fleece or a very thick base layer:
The North Face Salathe
Patagonia R.5

2. Go with a Gore Windstopper N2S (Next to Skin) piece:
Mountain Hardwear Transition
Marmot Evolution

These can be worn next-to-skin as a baselayer or as a midlayer, as well. These pieces are incredibly versatile and can be used year around. They wick moisture and block wind, though you do lose some of the moisture wicking property if the garment is not right against your skin (hence Next to Skin). If these options aren't warm enough, either bump up to a very thick base layer like the Patagonia R.5, or opt for a heavier fleece layer (see #1).

3. If you're participating in a high output, aerobic sport in winter, consider these two points: you will generate a ton of body heat that will keep you warm and 2) you will produce a lot of sweat. Accordingly, you'll want to use a thinner 2nd layer and one that manages moisture well. These days, many forego a mid or 2nd layer entirely and opt for a next-to-skin base layer (see #2) for awesome moisture management, and use a highly breathable outer shell like a soft shell.

4. Down or synthetic insulation like Primaloft are key here. The North Face Nuptse or the Mountain Hardwear Subzero Jacket are excellent options.

Outerwear these days can be multipurpose. Soft Shells, for example, have really changed the 2nd layer category because they can be used as an outer shell or as a 2nd or mid-layer due to their superb breathability and, to a lesser extent, wicking properties. Down is a must for insulation-it keeps you super warm in spite of being super light.

My personal layering system when ski touring in Utah is this: a Gore N2S (Next To Skin) base layer, like the Mountain Hardwear Featherweight Transition, and an Arc'Terxy Gamma MX Hoody as my shell. This system eliminates a 2nd layer altogether (or combines it with the shell depending on how you look at it). When I'm at the top of the run relaxing or eating lunch, I use a down jacket for insulation.

Climate definitely determines what types of materials to have in your quiver. Because I live in Utah, I can rely on soft shells rather than Gore-Tex shells-it's a desert here and the water-resistance of soft shells protects in all but the worst deluge or blizzard, in which case I bust out the Gore-Tex. If I lived in the Pacific Northwest, I wouldn't use a soft shell or down due to the region's moist climate. Instead I'd opt for a Gore-Tex Shell and a synthetic Primaloft filled jacket. Good luck!