Climate of Vancouver

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The climate of Vancouver, British Columbia is a moderate oceanic climate (Koppen climate classification Cfb) tempered by the warm Japan Current. The city is also sheltered by the mountains of Vancouver Island, to the west. These influences contribute to making Vancouver the warmest of Canada's major cities.^[1]

Contents 1 General conditions 1.1 Temperatures 1.2 Daylight 1.3 Statistics 2 Precipitation 2.1 Rain 2.2 Snow 3 Severe weather 3.1 Fall-winter 2006 storms 4 References

[edit] General conditions

The climatology of Vancouver applies to the entire Greater Vancouver region and not just to the city of Vancouver itself. While Vancouver's coastal location serves to moderate its temperatures, sea breezes and mountainous terrain make Greater Vancouver a region of microclimates, with local variations in weather sometimes being more exaggerated than those experienced in other coastal areas.

Predicting precipitation in the Greater Vancouver area is particularly complex. It is a general rule of thumb that for every rise of 100 metre in elevation, there is an additional 100 millimetres (1.2 in per 100 ft) of precipitation, so places such as North Vancouver on the North Shore Mountains get more rain. Snow has been particularly problematic for meteorologists to predict due to variations in elevation and the moderating effect of the coast on temperatures.

[edit] Temperatures

The coldest month on record at Vancouver International Airport was January 1950, with an average low of -9.7°C (14.5 F) and an average high of -2.9°C (26.7 F) making for an exceptionally cold daily average of −6.3 °C (20.6 °F) under the influence of the arctic outflow. Vancouver will become the warmest city ever to host the Winter Olympics in 2010.^[2].

[edit] Daylight

Winters in Vancouver can be dark, as the sky during this time is often covered with low-altitude grey clouds, and the relatively high latitude means early sunsets (as early as 4:15 pm) and late sunrises (as late as 8:05 am). For a few nights near the summer solstice, there are less than 7.5 hours between sunset and sunrise, twilight lasts past 10 pm, and the northern sky remains slightly lit by the sun all night.

[edit] Statistics

Vancouver Climatological Data
Temperature
Month		Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec		Year
Record high	°C (°F)	15 (60)	18 (65)	19 (67)	25 (77) '	30 (87)	31 (87)	32 (89)	33 (92)	29 (85)	24 (75)	18 (65)	15 (59)
Average high	°C (°F)	6 (43)	8 (46)	10 (50)	13 (56)	17 (62)	19 (67)	22 (71)	22 (71)	19 (66)	14 (56)	9 (48)	6 (43)		14 (57)
Mean	°C (°F)	3 (38)	5 (41)	7 (44)	9 (49)	13 (55)	15 (59)	18 (64)	18 (64)	15 (58)	10 (50)	6 (43)	4 (38)		10 (50)
Average low	°C (°F)	0.5 (33)	2 (35)	3 (38)	5 (42)	8 (47)	11 (53)	13 (56)	13 (56)	11 (51)	7 (44)	3 (38)	1 (33)		7 (44)
Record low	°C (°F)	-18 (-0)	-16 (3)	-9 (15)	-3 (26)	0.6 (33)	4 (39)	7 (43)	6 (44)	0 (32)	-6 (21)	-14 (6)	-18 (-0)
Average Precipitation and Sunshine Hours
Month		Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec		Total
Total	mm (in)	154 (6.1)	123 (4.9)	114 (4.5)	84 (3.3)	68 (2.7)	55 (2.2)	40 (1.6)	39 (1.5)	54 (2.1)	113 (4.4)	181 (7.1)	176 (6.9)		1199 (47)
Rainfall	mm (in)	139 (5.5)	114 (4.5)	112 (4.4)	84 (3.3)	68 (2.7)	55 (2.2)	40 (1.6)	39 (1.5)	54 (2.1)	113 (4.4)	179 (7.0)	161 (6.3)		1155 (45)
Snowfall	cm (in)	17 (6.5)	10 (3.8)	3 (1.1)	0.4 (0.2)	0	0	0	0	0	0.1 (0)	3 (1.1)	16 (6.4)		48 (19)
Sunshine	hours	60	85	134	182	231	229	295	268	199	125	64	56		1928
Data recorded at Vancouver International Airport by Environment Canada. Data spans 1971 to 2000.

[edit] Precipitation

[edit] Rain

Although popularly thought of as being a rainy city, Vancouver has only 166 days per year with measurable precipitation on average, and 289 days with measurable sunshine. Nonetheless, from November until March, it is not uncommon for there to be 20 consecutive days with some amount of rain. The weather pattern known as the Pineapple Express often brings warm rainstorms in the winter.

Thunderstorms are rare, with between zero to six occurring throughout the year,^{[citation needed]} as the Pacific Ocean (and the Strait of Georgia which funnels into the Pacific) does not get warm enough to produce the conditions needed. These storms are sometimes accompanied by hail and tend to occur more often in spring and autumn. The weather in spring and autumn is usually showery and cool.

Grass-cutting season often begins in February and continues until around October. Summers can be quite dry, and, as such, unwatered grass may not need to be cut for over a month. Some summers may have no rain for five weeks or more while others might have several very wet days in a row.

[edit] Snow

Snow occurs in the surrounding mountains and in the higher-lying areas of Greater Vancouver, such as Burnaby Mountain, Coquitlam, and North/West Vancouver. It is less commonly found in places which are at sea level. There is a general misconception among visitors and residents in other parts of Canada that Vancouver does not receive any snow at all, but in fact there has never been a winter in which traceable snow has not been observed at Vancouver International Airport. Environment Canada has ranked Vancouver in 98th place under the category of "Snowiest city" among 100 major Canadian cities.^[3]

Snow in Vancouver tends to be quite wet, which, combined with typical winter temperatures rising above and falling below 0°C (32°F) throughout the course of the day, can make for unusually slippery road conditions. Rain and sleet are almost interchangeable especially among higher elevations of the city.

Years or months with snowfall surpassing 100 cm (39.3 in) are not completely exceptional. Snowfall exceeding 100 cm occurred twice during the 1990s, and, in January 1972 alone, there was more than 120 cm (47.2 in) of snow. The snowiest year on record at Vancouver International Airport was 1971, which received a total of 242.6 cm (95.5 in), and the greatest snow depth reported was 61 cm (24 in) on January 15 of that year.

Although the 30cm to 60 cm (11.8 to 23.6 in) which fell across Greater Vancouver and the Lower Mainland in a 24 hour period in November 2006 was out of the ordinary, snow has in fact accumulated at sea level in all months except for June, July, and August. However, even small amounts of snow in the Vancouver area can cause school closures, as well as produce massive traffic problems. Snowfall levels considered routine or mild in other parts of Canada can be relatively catastrophic in Vancouver. Furthermore, the low frequency of snowfall makes it hard to justify the public works infrastructure necessary for more effective snow removal, as the city is usually in a thaw situation long before plowing of streets are completed. The City budgets CA$400,000 per year for the maintenance of snow removal equipment, for the purchasing of deicing salt, and for the training of staff, but the costs of actual snow removal are funded separately from contingency reserve funds, and vary widely from season to season. For example, $1.1 million was spent in 1998, compared to $0 in 2001. ^[4] Blizzards are rare but can incapacitate much of the Lower Mainland. One in 1996 resulted in over 60 cm (23.6 in) of snow in Vancouver and was responsible for millions of dollars in damage.

According to Environment Canada, Vancouver typically has a 13% chance of White Christmas. The most recent White Christmas occurred in 2007, with rain changing to snow and then back to rain in the lower elevations and coastal areas including Downtown and Richmond during the afternoon and the majority of Vancouver and its eastern municipalities receiving continuous snow since noon. The airport recorded 1.0cm of snow. The previous White Christmas occurred in 1998 when 20cm of snow was on the ground on Christmas Day following 31cm of snow and 20mm of rain.

[edit] Severe weather

Wind storms are not uncommon during the autumn months in Greater Vancouver. Three wind storms in the city's history have knocked down large swathes of trees in the forest of Stanley Park, the first having occurred in October 1934, with a blizzard the following January compounding its impact.^[5] The second wind storm to hit Stanley Park was the remnant of Typhoon Freda in 1962 that levelled a six-acre tract of forest. This is now site of the park's miniature railroad.^[6]

[edit] Fall-winter 2006 storms

Main article: 2006 storms in Vancouver, Canada

In November 2006, the Greater Vancouver region experienced above-average levels of rainfall and snowfall, breaking the previously-established record of 18.1 cm (7.15 in) when 25.5 cm (10.07 in) of rain fell within the first 16 days of the month.^[7] The heavy rain washed sediment into the city's reservoirs, and, as result, many businesses were advised to stop serving beverages prepared from tap water due to water contamination.

28 cm (11 in) of snow was recorded at Vancouver International Airport from the night of November 25 to the morning of November 27. The temperature dropped to −12 °C (10.4 °F) on November 28, 1.8 degrees^[vague] higher than the record low for the day, which was set in November 1985. In comparison, the day-time high in Toronto on November 28, 2006 was 16.1 °C (60.9 °F).^[8] 10 cm (3.9 in) more snow fell on the city on November 29. The snowfall resulted in the closure of a number of public institutions and caused power outages throughout Surrey and Langley.

The Hanukkah Eve Wind Storm of 2006 swept through Greater Vancouver on December 15, 2006 with winds reaching up to 70 km/h to 125 km/h. In Stanley Park, it damaged or uprooted over 5,000 trees, caused mudslides, and destroyed a section of the seawall.^[9][10] Insured damages throughout the province are expected to reach CA$40 million and repairs to Stanley Park are expected to cost $9 million.^[11][12]

[edit] References