related article:
Animal Rights - Change.org: From the Experts: Stop Dressing Up Dogs; To the Experts: Stop Saying "It"
From what I understand dressing up your dog can mask important smells that other dogs pick up on. I've seen dressed up dogs at the dog park - seems like they are always the ones to get picked on! :P
I don't dress up Lexi, she doesn't like it too much. It get's pretty cold here, but like I've said before in other threads. She doesn't mind the cold!
If she did mind the cold - I wouldn't hesitate on putting on her sweater.