it's the rain shadow effect that you are referring to:
Rain shadow - Wikipedia, the free encyclopedia
basically, the prevailing winds off of the ocean force the warm moist air up the slope of the mountain where it cools and looses pressure (adiabatic cooling) to the dew point (about 3 degrees Celsius per 1000 ft of lift). Once the dew point is passed, the air looses its moisture in the form of rain - thus the rany west side of the mountains, and it moves on in a dry form over to the east side of the mountains (dry interior of the Okanagan).
So far this month, Vancouver has had about 75 mm of rain. But Toronto isn't that far behind with about 73 mm. That's due to the jet stream being amplified and bringing moisture up from the Gulf.
I agree, Vancouver area has the best combination of mild climate, ocean/mountain juxtaposition as well as cosmopolitan and urban culture.