However as you probably discovered, Canada Goose products are very expensive . are you sure you want to spend that kind of money for a 4 day holiday? Montreal and Canada in general are cold in winter, but the period you are here is not the coldest part of winter. Personally I don pull my Canada Goose out until January/February, and rarely need it in the city. Dress in layers, with waterproof lined boots, warm gloves and hat.
Any of the main department stores downtown will have winter clothing La Baie (Hudson Bay Co.), Simons, Ogilivy, etc.
Although I, too, would question how useful such a good coat would be for warmer weather places. I have a Kanuk, which is basically the same thing, and the model I bought is rated from 0 to 30 C (32 to 22 F). I bought it a long time ago and it still going strong, and it light and amazingly warm, but I only wear it during really cold spells. Otherwise, I prefer layers and being able to unzip first one and then the other depending on how active I am or how hot the mtro is compared to outside, for example.