I’ve been backpacking through multiple generations of gear and clothing options. A lot of “latest and greatest” clothing materials have come in and out of popularity over the years. I’ve sworn by some choices that did the job, and sworn at others which performed poorly at inopportune times. I’ve developed a few clothing preferences for backpacking in cold, wet weather. For example, I always pack at least one wool layer for upper and lower body and feet: a wool stocking cap, long sleeve wool shirt, wool pants and wool boot sox. I usually wear a thinner inner layer under the wool, which varies as to material (but no cotton of course). I’ve watched wool go in and out of popularity a few times, and at times have even been criticized for choosing to wear it. Having been in situations where I have stayed warm, clear headed and functional in my wet wool, while others have suffered the onset of hypothermia in their synthetics, it’s hard for me to leave wool at home. But maybe I’m overlooking something that is truly a better choice for when you just KNOW that no matter how good your outermost layer is, you WILL be wearing wet clothing for a few days. What are others choosing for days of unavoidable cold wet weather (besides staying home), and is wool one of your choices?
I love my wool top and bottom baselayers, and when it's cold and wet I use a synthetic hoody and puffy over them. I haven't found outerlayer wool pants or shorts that I like, but I'd be interested to try. I think the wool base has kept me warmer than synthetic baselayers, and always wool socks! I like synthetics for being lighter and drying faster, so a blended system works well for me.
I agree with @runaround. I usually go with a wool baselayer, followed by synthetcs and jacket/coat. The jacket coat is usually something with down in it. I find wearing a synthetic on the outside snags less, and having the wool next to my skin keeps me warm in most conditions (with suitable outer layers).
I've always sworn by wool for colder to mid temps, and even in warmer conditions it still earns its place in my pack. Synthetics are great for sunnier/dryer days for me, and I love my synthetic shirts for getting warmer hikes in. When the conditions turn though, I've never been dissapointed wearing wool, while other materials have not lived up to the standard of wool. I really got my affinity for wool from family in Alaska who always love their wool socks and baselayers. It's never let them down, and if its good enough for rural Alaska, I figured it would be good enough for me, and in my adventures its never let me down.
I have thought many of the same thoughts you are having. I base my clothing selection on the weather most off. I get particularly warm and sweaty when getting outside so I will tend toward synthetics for warmer conditions. When it will be cooler temps or at night, I will reach for at least a wool baselayer.
I prefer synthetics over wool, finding synthetic to be just as warm, gnerally more durable, and quicker to dry. over the years, most of my outoor wardrobe has become synthetic.
Much of my experience has been in mountain SAR, not inrequently under adverse conditions (cold and wet). For equivalent weight and thickness, I will go non-wool anytime.