I just retired to rural south central Alaska with my GSD (Qanuk) and my Alaskan Malamute (Anana). Both dogs are extremely active but Qanuk is just addicted to regular and extended duration exercise. Its not uncommon in this area (7 miles south of the town of Talkeetna) to see winter air temps of -30 F and sometime even lower. In addition by January the snow pack is normally over three feet in depth but the roads are usually kept plowed. I am concerned about having Qanuk outside when the air temp is in the - 20 F to -40 F range; however, I know he will demand exercise even at such low air temps so I was wondering if there are any accepted guidelines for the lowest air temps a short haired GSD should be outdoors in and for how long a time? He is in excellent shape, weighs 85 pounds and is 25 months of age.