I cheated and drove in today. It was 12*F which in and of itself isn't too bad. The problem was that I had my commuter gear and slicks on my Outlook from yesterday's fair-weather commute, but didn't have time to swap the gear or the wheelsets between the bikes and still make it to the bus on time. There was tons of standing water yesterday, and that would have been a solid sheet of ice. Not doing that on slicks.