Calgary is known for having a prairie-steppe type of climate. Meaning it normally has very sunny weather, even in the winter months, and most of the rainfall comes in the summer time. Calgary and the surrounding areas have many farms and acreages, so the summer rain really helps the wheat and grass growing there.
Also due to being in a prairie location, Calgary also has a windy climate. This wind sometimes can turn into a Chinook, which is a hot, dry, Foehn wind that comes down from the Rocky Mountains. This helps in the cold Calgary winters, as the Chinook can warm the temperature by 30 degress centigrade in just a few hours.
In the summer time Calgary is very dry, which is perfect for people who dislike humidity. The summer nights are also known very being quite cool.