Oh, and as far as good jackets go... Depending on how much you are willing to pay, Ruffwear stuff gets RAVE reviews. I am hoping to save up and get Jackson a GOOD coat. He's got a few from Walmart, etc, and they do the job, but a lot of times they get very wet themselves, so makes him colder. I really want one that truly does the job, and RuffWear seems to be it. Also, Hurtta makes some very nice jackets. But they run betwen $60-$80, so ... It's kind of a splurge!
Yorkies obviously were not meant to withstand the cold like a Husky, hehe, but most I see fair pretty well. The rule of thumb is usually if you need a jacket, they need a jacket. But for quick potty breaks, I am sure she will be fine.
Check out AlaskaYorkie... Mike's dogs live in Alaska and are very snow-adventurous Yorksters!