It’s been over 15 years since I was a winter bicycle commuter, and I’ve been eager to see what my lower threshold would be. Today exceeded it. This morning the temp was 11° and the windchill was -4°. My rule of thumb is now either < 15°, or (more likely) < 0° windchill. My fingers get too cold, and I can’t tolerate any more loss of dexterity to insulate more. My toes, legs, and other parts got a bit chilly too, not to mention freezing my windward ear while I was standing at the bank drive through.
My bike computer didn’t like it either, though I’m puzzled why my chain and derailleurs were sticking. Maybe those are unrelated?
Anyhow, it never gets too cold to walk, so now I know when to hoof it.