I've got a satisfied smile because I was camped well north of the Arctic Circle, up in the Alaska National Wildlife Refuge for nine days last years. It was actually sunny, but not particularly warm when I took the selfie. Before the trip I took the plunge and bought my first down jacket in over 30 years... This is the "Super Down Ultra Jacket" by Kuiu.
It's very light, only about 6 ounces total! Crushes into a small enough bundle to fit inside a pocket on my backpack. It's made to be worn like a thick, insulating shirt or sweater. Over the base layer, and under the shell garment.
Amazingly, they high-loft goose down has been treated so that water does not affect the insulating abilities! That was the downfall, pardon the pun, of older down garments. It's not an inexpensive jacket, but it's so light, comfortable and warm, that perhaps it should be considered by those who venture into cold climes.