James, for me it's more of the way weather makes me feel. Perhaps I've had to ride to a location far too often sopping wet and chilled from the air. The worst feeling for me--besides an empty refrigerator--is that cold, penetrating wet feeling. That soaked feeling that resists a warm-up without trembling.
(As a younger man I carried no spare clothes or even dry socks for a weekend get-away. If it rained all weekend, I sat in wet clothes for the entire run. Contrary to popular thought, a leather jacket is not warm. I shivered.)
On the other hand, I usually wear an unlined jean jacket for most of the winter unless we have those 40 below zero days.
Note: I'm not sure this little Sportster is an 'all weather' vehicle. If you ever get to examine a '48' you'll find that most of the mechanism(s) are are on the outside of the engine. Besides the wheel and their bearings that would get a high-speed soaking, it seems that every wiring loom, hydraulic line, motor mount and this bizarre 2-foot long Johnson rod that activates the rear brake are all exposed to the elements. Yeah, it's a Sportster, I know it's a bike designed to go two miles to the nearest tavern...