I remember a 20F (-6C?) day doing 70 or so on my Interceptor. The engine never really warmed up; I kept swapping which leather-gloved hand was holding the exhaust pipe right by the head so my hands wouldn't freeze. That was an interesting ride. The day before it was 10F, and I only rode the bike 7 miles to a co-worker's house to ride the other 20 or so with him. The day before that was 0F, and my wife was off so I took the car. It never got warm enough to idle without extra gas. I had to keep it at 2K RPM or higher or it would die. On the interstate, I was going 70 in 4th instead of 5th. I had the heater off because it leeched heat from the engine. Not a normal Atlanta winter, thankfully.