I wonder when it was that our ancestors worked out that wearing the fur of the animals they ate would allow them to leave the savannah and venture further afield? Without a doubt clothing of plant fibres where a later development so I feel safe in assuming that it was fur clad man who originally crossed the glaciers and populated the world!
Why do I point this out? Well with the chilly weather and the forth coming Winter WEISS my thoughts have turned to cold weather clothing - I'm a complicated soul eh!! ")
There is a simple equation for the outdoors man when is comes to insultion -
Pile clothing is better than fleece and down is better than pile!!
This is a generalisation and doesnt take into account synthetics like thinsulate ect ect.
So what does that knowledge do for us? Well it means we understand that a pile fleece like a helly hansen field jacket is warmer than a standard polartec type fleece - it also arms us with the info that pound for pound in both weight and cost down is still the best insulator.
Many people go on about the qualities of Wool and I agree as base and mid layers wool is excellent for its wicking, insulation and nonodour properties - but for outer layers such as jackets or for heavier insulation then the above comes into its own and wool is found wanting (ever worns a soaked woollen jacket or jumper?).
My own dress code for the cold - winter weiss with temeperatures down to say -12c is a thin and medium wool layer under a windproof smock while active - over this I add a down vest for rest stops ect. If inactive in the snow I'll wear a snugpak Sleeka under the windproof and keep the down in my daysack for emergency use or incase the temperatures drops further!!