You don't wear a normal blazer at -35C. And it's not a puffy coat, it's not even an inch thick. You are thinking of the coats from the early 2000s. It's not like that at all.
That's why you have a coat that goes over your sports jacket/blazer/suit jacket/whatever. An...overcoat. Also, at -35c that's not going to keep you warm at all. All the heat gets let out since it doesn't cover half your chest and seems pretty loose letting all the warmth out the bottom.