I've been mid 50's lately.
Roads are usually deep slush or when it's too cold, packed snow the salt can't melt. It was -3F (-20C) yesterday when I left for work, sometimes I idle the car a bit before leaving because at those temperatures the steering wheel burns my hands even though the thin gloves I like to wear. We've also had a few days where the ice has been bad and it has taken me 3.5 hours to make it the 10 miles / 20 minutes to get home, a lot of accidents and roads closing down. Idling 3.5 hours certainly can't help economy.
Still pleased to be getting this economy.