This might sound absolutly horrifying to you all, but right now it is like 6 degrees farenheit, and my dogs stay outside all the time. And none of my dogs have that long of hair. They all have dog houses the people could live in ( they have insulation and windows and everything, VERY warm) but even so, some PTers probably disagree a lot with this, but my dogs have lived outside there whole lives. Boo boo has for 13 years, and at night it averages about -5 F.