The weather phenomenon that makes Calgary so livable is called the Chinook.
It's not unique around the world, but when it's -30 around most of Alberta, the Chinook is certainly the most welcome. It gives us a reprieve from the icebox bringing the temperatures back up close to zero and even +10 at times.
Needless to say, while the rest of Canada is living in an icebox from anywhere from -20 to -40, Calgary are "Basking" in sunny skies & above freezing temperatures. The margin for getting the benefit of the effect is quite small. Typically there band of warm weather runs from about 5kms from the foothills of the Rockies, to about 80kms out. This usually means Calgary is right on the edge. The narrow band of warm air is accompanied by clear skies & the boundary is distinctly marked by a cloud front (above).
