I've taken 13-mile trips (mix of city and freeway) in temperatures of less than 10 when the battery never came on despite a full charge, or only came on for a minute or two. Leaving the car outside overnight doesn't help the cause either, but I have no choice on that one since we only have room for one car and I leave for work an hour earlier than my wife. I have gotten over 40 during those days when the temperatures have been over 50, so I'm definitely looking forward to Spring.