I'm missing my cat in Toronto!?

My cat just went missing outside. I live in Toronto, so there is quite a bit of ice and snow outside right now. It's quite windy as well. It's been missing for less than 24 hours right now.... I'm not quite sure what to do, my cat is a small short hair and just a little over 4 months old. I left the door towards my porch (it is enclosed) open. But I am quite worried and I was wondering if there is anything more that I can do.

I've gone looking for it for quite some time now and still nothing. I've heard that cats can survive cold weathers but I most of the articles do not mention the cat's age or anything of that sort.

Any information is helpful =(