@ascentale @MarkBrigham @bikenite I've done it down to -11F with the right clothing and planning it's fine. I will get my clothes sweaty so I always carry dry layers that I can stand still in case something goes wrong and I have to stop. Only thing that really prevents me is if it's too sloppy and I have to share with cars.
I can maintain myself much better than most people can drive, and usually it's harder to walk on ice after I stop than to ride.