Many metals exhibit what is known as a ductile to brittle transition as the temperature goes down. This is not linear and happens fairly suddenly in a pretty narrow temperature range. Above this temperarure range, the metal will bend before breaking and require a harder impact to break. Below this temperature range, there will be almost no bending before breakage, the broken surfaces are very clean, and less of an impact will cause breakage. Steel is one of the metals that suffers from this. I've never really heard of this being a problem w/ knives. It is a winter time problem w/ axe heads in the NC mountains, where I'm from. Of course, Fairbanks is a little bit colder. 300 series stainless steels do not have this property. They do get more brittle as temperature decreases, but its not a sudden and deep drop off, like that seen in carbon steel and hardenable stainless steels.
I sometimes do impact tests on bridge girder material at work. We occasionally get mild steel samples that can take 300 ft*lbs of energy and not completely break. This is at 40 degrees Farenheit. The same samples will snap and fly across the room at -40 degrees, and only absorb about 50 ft*lbs.
Satin, any steel that has a reputation of being tough, such as A-2 or 5160, should be fine. Axes are ground a little thicker toward the points of the edge than in the middle to deal w/ this problem. You may not be able to grind the edge as thin as you would like. Neoprene is an excellent insulator, and should work fine with respect to cold weather conditions. Its used in gloves and mittens. You'll have to look into its ability to deal w/ the stress of being a knife handle though. You may want to think about a way to isolate the tang from the hand, to prevent the user from touching ice cold (or colder) steel.
