It's in a high mountain valley with a floor that lies at 7700 feet at it's lowest point. It is surrounded by 14,000 foot peaks and ranges in basically every direction. The cold air settles to the bottom of the valley most of the time. Usually there is an inversion during the winter and it's colder in the lower parts and valley floor than up high. Many times during the winter Gunnison is the coldest place in the country.
Yeah this guy knows his stuff. It is also a pretty closed in valley, so the cold air just settles instead of getting blown out. A few days ago, it was about 60 in Denver and it was -8 in Gunnison...in the afternoon.