re: How cold is too cold to leave a lab outside during daylight hours?

I had a German Shepard when I lived in Montana. My wife always felt like it was too cold for her outside in wintertime(she did come in at night). Til we went for a hike and she jumped in a creek with snow and ice piled up on the banks and rocks. She could get in the garage when we weren't home and normally rather be outside during the day.