Climate in British Columbia is influenced by latitude, mountainous topography and the Pacific Ocean.
This diversity causes wide variations in average rainfall, snowfall, temperature and hours of sunshine, sometimes over very short distances.
In general, however, temperatures are warmer in the south than in the north, and rainfall is heaviest along the coast and lightest in the southern interior. BC is a large province, and therefore has a number of different climatic zones.
Current BC weather conditions
Winters on the coast are temperate, and if snow falls it doesn't stay long. A warm coat and umbrella are sufficient weather protection in these mild coastal climes. Most of BC's interior, on the other hand, experiences freezing temperatures and snow lasting from November to March, so full winter wear is necessary for comfort: a heavy coat, a warm hat and gloves or mittens.
Spring and Fall
Spring and fall can often be very warm and pleasant, especially in June and September. Daytime temperatures – particularly in southwestern BC and the southern interior – allow for dresses, shorts and short-sleeved shirts; however, it is advisable to have sweaters, trousers and a light coat or jacket on hand as well.
Summers are hottest in BC's interior, particularly in the south where temperatures frequently surpass 30°C/86°F. Nearer the coast, temperatures range from 22 to 28°C/72 to 83°F. Recommended clothing for both regions in summer is the same: shorts, short-sleeved shirts and light dresses in daytime and sweaters and trousers in the evenings.
Coast Mountains & the Islands: Generally an area of heavy precipitation. Apart from a wet regime, mild temperatures and long frost-free periods are the rule.
The windward outer coast of Vancouver Island – including Tofino – receives the greatest amount of annual rainfall. The Georgia Basin, which includes the east coast of Vancouver Island, the Gulf Islands, Vancouver and the Sunshine Coast, lies in the rainshadow of Vancouver Island. This more protected region has considerably less precipitation and a greater quantity of sunshine. For example, Vancouver's average maximum temperature is 6°C/43°F in January and 22°C/72°F in July, and its annual rainfall is less than half of Tofino's. Autumn and winter still tend to have heavy precipitation.
The north coast – including Prince Rupert – typically receives greater annual precipitation than the Georgia Basin and cooler temperatures due to its higher latitude.
Higher elevations in the Coast Mountains get heavy snowfall in the winter.
The Interior Plateau: Because the Coast Mountains act as a barrier to the moist westerly air flow, the Interior Plateau (immediately to the east of this mountain chain) has a much drier and more continental climate. Summers tend to be warm and dry; winters cooler, but less moist. The southern interior, including the Okanagan, Similkameen, and Thompson River valleys, experiences BC's hottest summers, with temperatures often in the 30°C range/86-102°F, and occasionally rising above 40°C/104°F. Kamloops, for example, has an average maximum of -1°C/30°F in January and 28°C/82°F in July, and just 279mm/11in of annual precipitation. Areas further north on the Interior Plateau (Williams Lake and Prince George areas) tend to have a moist, cooler regime than that of the southern portions of the plateau.
Columbia Mountains & Southern Rockies: This region is in the southeast portion of the province and has marked contrasts in climate. The valley bottom localities are semi-arid with warm summers and cold winters, like those found in the Grand Forks or Cranbrook areas. Cranbrook has an average maximum of -3°C/27°F in January and 26°C/79°F in July, with 383mm/15in of annual precipitation. Upslope, and on the windward slopes of the Monashee, Selkirk, Purcell and Rocky Mountains, much higher precipitation and cooler temperatures are evident (such as in the Revelstoke area).
Northern and Central Plateaus & Mountains: This interior region in northwestern BC (including Dease Lake, Smithers and Mackenzie) has much colder winters and cooler summers. The winters are generally colder and drier the further north one travels. Summers are short and fairly cool, though the long days partially compensate for these conditions. Precipitation, though quite light, is distributed evenly throughout the year. In Dease Lake, for example, the average maximum temperature in January is -13°C/9°F and in July is 19°C/66°F.
The Great Plains: To the east of the northern Rocky Mountains, in the northeastern portion of BC (such as the Fort St. John and Dawson Creek area), lies an extension of the Great Plains so evident in the provinces of Alberta, Saskatchewan and Manitoba. This area experiences long, cold winters and short, warm summers, with a relatively high number of sunshine hours, a wide range in seasonal temperatures and a precipitation maximum during the summer months. Dawson Creek, for example, has an average maximum of -9°C/16°F in January and 22°C/72°F in July.