-20 C is extreme cold ? You can still go out and do stuff, just get a decent coat. We don't get very harsh winters here, I think -8 C or so would be a good temperature to see it as being in winter in your mind's eye. Yet people prance about in these $800 down coats meant for far colder weather (well, I think they are, anyway)
It does make getting out bed difficult when you hear it's -30 C with wind out though.