It occurred to me today this winter I will accumulate more time and miles riding over longer distances at higher speeds in colder weather than I have ever done in my twenty-five plus years of riding. That'll be fifty miles a day, five or so days a week, almost all of it at (...or above...) highway speeds.
My commute is just about twenty-five highway miles, with a brief transit of a small town in the middle; that translates into about 35 minutes on the road. This morning, the temperature at home was 20° f., making the wind chill while riding about -7° f. Thirty-five uninterrupted minutes of that kind of exposure is just about plenty; knowing there's a warm place at the end helps quite a bit. Generally speaking, as long as you can block the wind, it's okay; but you feel the gaps you missed—like around the visor—where wind cuts through like jets of icy fire into your skin.
I think it's safe to say this ride wouldn't be practical or possible without assistance. My Gerbing electric jacket, umbilicalized into Beast's innards, does the heavy lifting; Beast's heated grips do their part. There's simply no amount of insulation that can keep you warm under those conditions—you must have something providing a source of supplemental heat or you'll find yourself making poor decisions from hypothermia-induced stupidity in no time.
It's amazing what a difference heated clothing makes; so much energy goes from the bike into keeping me happy that I can actually notice a drop in my gas mileage from the heavy electrical draw. But it's worth it, as I am still able to use the 45 mpg bike instead of the 12-mpg truck.
So twenty degrees is the benchmark so far this season; I can't quite remember what it was in the winter of 2006-2007 (as far as riding season; I do recall it got below zero for a morning or two...I'll even concede that riding is out of the question at that point, at least for this old man.)
But as long as the roads stay clear and dry, Beast and I will make a go of it, I think.