People have different ideas of extreme cold. To me, -20 C is not "extreme cold" and I expect my car to start right up so long as I have not gone many days without using it. I would consider -30 or -40 C to be extreme cold. I get the feeling that maybe other people consider 0 C to be extreme cold. Where I live, it's not -20 C all winter, but it does get that cold a few times a year.