Generally, the Islands and the Vancouver, Coast and Mountains region is an area of heavy, winter precipitation. Apart from being rather wet, winters are fairly mild, and relatively cool summers are the rule. Victoria is the only city in Canada that has recorded winters when the thermometer did not drop below freezing. The west coast of Vancouver Island is exposed to the moisture-laden westerly winds blowing off the warmer Pacific Ocean. The warm air masses are forced up by the island's mountain ranges resulting in considerable precipitation falling on the Pacific Rim region during the winter months of September to March.
Summers are relatively dry.
The location of the Gulf Islands , frolicking in the rain shadow of the Vancouver Island mountains, ensures a moderate climate with warm, dry summers and mild, wet winters. The Coast Mountains are an effective barrier to the moist westerly air flow. To the east of this mountain chain, on the Interior Plateau, there exists a much drier and more continental climate. The valley bottom localities are semi-arid with warm summers and cold winters, like those found in the Grand Forks or Cranbrook area. The northern half of the province has much colder winters and cooler summers.