There are two major aspects to the weather in Vancouver - the seasonality and the geography.   Vancouver is characterized by cool, wet winters, and warm, dry summers. People think it rains in Vancouver all the time, and they're half right. It rains a lot (a lot!) from late fall to mid-spring. From mid-October to mid-April, Vancouver gets most of its rain. On the other hand, it's possible to go weeks without rain in the summer, prompting announcements of water shortages and lawn sprinkling restrictions. It's a little known fact that Vancouver actually receives less rain in the summer than Toronto.

The temperatures are very mild (considering that this is Canada!), meaning that it rarely gets really hot (i.e. over 30 C or 90 F) or really cold (below 0 C or 32 F). There may be about a week where there will be snow on the ground, usually in January. Sometimes (about once every eight years or so), there will a cold snap of such depth and duration that Lost Lagoon will freeze over, and people will actually be able to skate outside.

In the summer, Vancouver doesn’t get the humidity to the extent of other cities in the eastern portion of the continent, thus making summers quite comfortable (relatively few people in Vancouver have air conditioning in their homes). Finally, the maritime aspect of the city generally results in a cool westerly breeze from the water most summer days, which keeps the temperatures in the western half of the Lower Mainland about 2 - 5 degrees cooler than the Fraser Valley.

The second major thing to remember about Vancouver is the affect that geography has upon the weather. Especially in spring and summer, clouds may gather and rain may fall near the mountains, but it may be clear and sunny in the southwest "flats" of Richmond, Ladner and White Rock. Portions of the North Shore (Lynn Valley, for example) receive approximately twice the rainfall of a location like the BC Ferries terminal in Tswwassen. In the winter, the geography has less impact, since winter rain is brought on by large frontal systems emanating from the Gulf of Alaska (which impact the entire region), rather than the convection-fueled rainfall of summers.

 ** Note:  The original information for this thread came from the following forum thread: http://www.tripadvisor.com/ShowTopic-...