The sheer size of western Canada makes for different climates
and radically varying temperatures, which rise or fall with
changes in elevation, latitude, slope aspect, and distance from
the ocean. The coastline of British Columbia boasts the mildest
climate of all Canada, but this comes with one drawback—it rains
a lot. The two main cities, Vancouver and Victoria, lie within
this zone. As prevailing moisture-laden westerlies blow across
British Columbia, the cold heights of interior mountain ranges
wring them dry, producing drier, hotter summer temperatures and
sunnier skies the farther east you travel. The same is true in
winter, except the temperature range is reversed—winter
temperatures in Calgary are lower than in the interior of
British Columbia and significantly lower than in Vancouver. In
winter, the dry winds blasting down the eastern slopes of the
Canadian Rockies can raise temperatures on the prairies by up to
40°C (72°F) in 24 hours. Called chinooks, these desiccating air
currents are a phenomenon