20.2 mpg?? How the hell do you manage that? I'm lucky to get 16 and I drive like an old lady. Mostly on the highway.
I got that the other day, too, but I don't remember the temp hitting 32 degrees. This was in San Jose.
The warning comes on at 37 degrees, it alerts you that it's getting near freezing.
Or that there are ninjas in the area.