Dogs actually don’t need dog coats. Now that’s not to say that you can’t get them one and make them look all snug like a bug in a rug but biologically coats are not needed. Most dogs (unless for medical reasons such as Alopecia) have enough fur to keep them nice and warm during those winter months.
Reference:
https://thedogsstuff.com.au/blogs/news/things-to-know-before-buying-dog-coats