Merino wool is the most efficient material for cold weather. Merino wool is softer than regular wool, and it feels more like cotton against the skin. Merino wool resists wind and warms better than synthetic materials. It doesn’t absorb odors and it regulates body temperature. It is also produced in a sustainable manner.
The jacket pictured here is the Smartwool Yampa Jacket. It’s designed with a woven wool sueded fabric, and it has a heavy 100% merino wool lining. There is a women’s version of this jacket too. Smartwool sells a whole range merino wool clothing, including summer wear. Merino wool clothing tends to be expensive, but you can find Smartwool at Altrec.