- Geography of Toronto
-
Toronto's skyline from its harbour The city of Toronto, Canada, covers an area of 630 km2 (243 sq mi) and is bounded by Lake Ontario to the south, Etobicoke Creek and Highway 427 to the west, Steeles Avenue to the north, and the Rouge River to the east. In addition to Etobicoke Creek and the Rouge River, the city is trisected by two minor rivers and their tributaries, the Humber River in the west end and the Don River east of downtown. Both flow southward to Lake Ontario at Humber Bay and Toronto Harbour respectively, which are part of the longer Waterfront.
The concentration and protection of Toronto's ravines allows for large tracts of densely forested valleys with recreational trails within the city. 17.5% of Toronto is covered with trees,[1] a fairly high percentage within a large city in North America and there are ambitious proposals to double the coverage.
Scarborough BluffsThe shoreline of the former Lake Iroquois is a major west−east geological feature which was formed at the end of the last glacial period. In the west end, Davenport Road follows the ancient shoreline with the steps to Casa Loma rising above and downtown skyscrapers clearly visible to the southeast. It merges with current Lake Ontario shoreline at the Scarborough Bluffs promontory.
Toronto's immediate neighbours are Mississauga and Brampton within the Regional Municipality of Peel, Vaughan and Markham within the Regional Municipality of York, and Pickering within the Regional Municipality of Durham. The Greater Toronto Area (GTA) includes the regional municipalities of Halton, Peel, York and Durham.
The GTA is part of a larger, natural ecosystem known as the Greater Toronto Bioregion. This ecosystem is bounded by Lake Ontario, the Niagara Escarpment, and the Oak Ridges Moraine, and includes many watersheds that drain into Lake Ontario. Some parts of Toronto, such as High Park and the lower Humber River are located in the most northern parts of the Carolinian forest zone found in North America.
In March 2005, the Government of Ontario unveiled the boundaries of a greenbelt around the Greater Toronto Area, a 7,200 km2 (2,800 sq mi) area stretching from Niagara Falls to Peterborough. The green belt is designed to curb urban sprawl and to preserve valuable natural areas and farmland surrounding the city. Toronto is the latest in a line of cities that have implemented growth boundaries of some kind as a method of restricting urban growth, including Ottawa, Portland, Oregon, Frankfurt, Melbourne, Seoul and London, UK.
Contents
Climate
Toronto Climate chart (explanation) J F M A M J J A S O N D 61−1−7510−6665−270114731910722415682618702517832113651477672712−4Average max. and min. temperatures in °C Precipitation totals in mm Source: Environment Canada Imperial conversion J F M A M J J A S O N D 2.43019232212.640282.852392.965502.874592.780642.878633.369562.65745345362.83525Average max. and min. temperatures in °F Precipitation totals in inches Toronto's continental climate is moderated by Lake Ontario; its climate is among the mildest in Canada east of the Rocky Mountains. It sits in a pocket of the humid continental climate (Köppen climate classification Dfa) climate zone found at the south-western end of Lake Ontario covering the southern part of the city - including downtown, where the annual average temperature exceeds 9 °C (48 °F). There is a high degree of variability from year to year and sometimes even over a period of days, particularly during the winter months.
Lake Ontario's water temperature varies due to upwelling of colder water or warmer pools of surface water creating very localized thermal contrast; the deeper waters of the lake remain at a near constant water temperature of 4 °C (39 °F), the effect of which is either cooling or warming (in winter). This creates generally warmer nights through the colder season. When offshore winds occur in summer, they warm as they blow toward the lakeshore in the evening; conversely, the cooling effect by the lake is most pronounced on spring afternoons, which affects Toronto even more than other cities on the Great Lakes as during spring onshore east to southeast winds are predominant, on some days the temperatures can be as much as 10C cooler than areas south of Lake Ontario away from its influence, an effect that wanes by summer when the dominant windflow becomes more southwesterly.
Springs and autumns feature varied weather with alternating periods of dry, sunny weather and rain. These seasons are brief when compared to summer or winter seasons, many days are sunny with pleasant temperatures. Nights are generally cool, but frosts are rare. Snow can fall in early spring or late fall but usually melts quickly after contact with the ground. At these times of year, great temperature contrasts (up to 30 °C (54 °F)) can occur within a short time frame due to rapidly changing air masses that sweep across the continent.
Annual average precipitation is 834 mm (32.83 in).
Winter and snowfall
Despite being cold, extended snow free periods occur in most winters. The average January maximum/minimum is −1 °C (30 °F)/−7 °C (19 °F) in the city.[2] There are usually a few colder periods where temperatures remain below −10 °C (14 °F) and less frequently below −20 °C (−4 °F) (especially in the northern suburbs), with wind chills making it feel like −30 ºC (−22 ºF).[3]
Due to its position on the northwest shore of Lake Ontario, Toronto is not a direct target of heavy, wind−whipped lake-effect snow squalls that hit other Great Lake cities on the south/east shorelines of the lakes, in areas where prevailing winds amplify lake effect. Despite this, there are usually two or more heavy snowfalls each winter which deposit at least 15 cm (5.91 in) accumulation, usually from powerful winter storms known as "Colorado Low"s or Panhandle Hooks. These storms can produce strong easterly driven winds that fetch additional moisture from Lake Ontario. They frequently come with a volatile mix of snow, ice pellets, freezing rain and ordinary rain, all of which can disrupt transportation, and in severe cases, power supply in the area. Lighter, drier snows generally originate from Alberta clippers. Average winter snowfall is 133.1 cm (52.4 in) at the weather station in Downtown Toronto[2] and 115.4 cm (45.43 in) at the airport.[4]
Exceptional winter weather can create havoc. On January 13, 1999, former Toronto mayor Mel Lastman called in the Canadian Forces to assist with snow removal and clearing streets. Within twelve days, the downtown Toronto weather station at the University of Toronto (Trinity College near Queens Park) recorded an average season's worth of 118.4 cm (46.6 in) of snow, much of it lake effect from Lake Ontario and a monthly record for January, but fell short of the snowiest month overall (March 1870, with 158.5 cm (62.4 in)). February 2008 set a record a snowfall record for the month with 76.8 cm (30.2 in) falling at the airport. The winter of 2007−08 brought accumulated seasonal snowfall totals of 209.7 cm (82.6 in) downtown and 194.0 cm (76.4 in) at the airport, which did not break the all−time records but was the snowiest in recent memory: 313.7 cm (123.5 in) downtown (1869−70) and 206.7 cm (81.4 in) at the airport (1938−39) still hold as the snowiest winters (Note: climate records downtown date back to 1840 nearly 100 years earlier than the airport, which go back to 1937). The El Nino influenced winter of 2009-10 set records for the least snowfall with close to 50 cm (19.7 in) falling during the entire season, March 2010 recorded no measurable snow, the first such occurrence in any March since 1946. This was followed by the record warmest April.[5]
Toronto skyline taken from Colonel Samuel Smith Park in Etobicoke.Maximum temperatures typically range from 23 to 31 °C (73 to 88 °F) with moderate to high humidity, proximity to Lake Ontario and the other lakes contribute to summer moisture content but far away sources like the Gulf of Mexico also factor in. Temperatures over 32 °C (90 °F) occur but usually no longer than over a period of a few days and they very rarely exceed 38 °C (100 °F). Night temperatures generally hover close to 20 °C (68 °F) in the city. Summer heat episodes are usually broken by cooler, drier periods not experienced further south on the continent. But intense heat episodes pose a health risk to some as they often arrive with high humidity and dangerous levels of airborne smog.
Thunderstorms are a regular occurrence and can pop up quickly, especially west and north of the city in areas more prone to the "lake breeze front" or "lake breeze thunderstorms" phenomenon, in which intense, sharply defined squall lines develop quickly on summer afternoons amplified by localized wind patterns between the Great Lakes.[6] These storms sometimes move into the city causing localized flooding, intense lightning and severe winds knocking down trees and powerlines.Based on public records provided by Environment Canada, the average annual temperature has increased 1.3 °C (2.3 °F) at Pearson Airport over the last decade as compared to the thirty−year normals from 1971−2000, more of this increase occurred at night: the average minimum temperature was 1.7 °C (3.1 °F) higher last decade. By month, the largest mean temperature increases occurred in September, August, January, April and November while only a marginal average increase was observed for May. A good part of this warming can likely be attributed to increased urban growth surrounding the airport.
An older study conducted in the 1990s analyzed the heat island effect comparing data from selected regional stations, including both Downtown Toronto and Pearson Airport.[7]
The table below is preliminary average temperature data for the last decade provided by Environment Canada's climate database. It might be noted that the decades between the 1920-1950s were somewhat warmer in Toronto than the period from the 1960s through to the first half of the 1990s, a large part of the latter timespan is included in the 1971-2000 climate averages.
Climate data for Toronto Pearson International Airport 2001-2010 Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Average high °C (°F) −1.1
(30.0)−0.3
(31.5)4.9
(40.8)13.0
(55.4)18.7
(65.7)24.6
(76.3)27.3
(81.1)26.8
(80.2)22.8
(73.0)14.6
(58.3)8.6
(47.5)1.7
(35.1)13.5 Daily mean °C (°F) −4.8
(23.4)−4.3
(24.3)0.5
(32.9)7.8
(46.0)13.2
(55.8)19.4
(66.9)22.0
(71.6)21.6
(70.9)17.6
(63.7)10.2
(50.4)4.7
(40.5)−1.7
(28.9)8.8 Average low °C (°F) −8.5
(16.7)−8.3
(17.1)−3.9
(25.0)2.6
(36.7)7.6
(45.7)14.2
(57.6)16.7
(62.1)16.4
(61.5)12.3
(54.1)5.7
(42.3)0.7
(33.3)−5
(23)4.2 [citation needed] Climate data for Toronto Downtown (The Annex) 2001-2010 Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Average high °C (°F) −0.3
(31.5)0.5
(32.9)5.3
(41.5)12.6
(54.7)18.4
(65.1)24.3
(75.7)26.8
(80.2)26.5
(79.7)22.4
(72.3)14.5
(58.1)8.9
(48.0)2.4
(36.3)13.5 Daily mean °C (°F) −3.4
(25.9)−2.9
(26.8)1.8
(35.2)8.6
(47.5)14.0
(57.2)19.8
(67.6)22.4
(72.3)22.2
(72.0)18.2
(64.8)11.0
(51.8)5.9
(42.6)−0.5
(31.1)9.8 Average low °C (°F) −6.5
(20.3)−6.2
(20.8)−1.8
(28.8)4.5
(40.1)9.6
(49.3)15.3
(59.5)17.9
(64.2)17.9
(64.2)14.0
(57.2)7.4
(45.3)2.8
(37.0)−3.3
(26.1)6.0 [citation needed] Severe weather and records
Tropical storms, very severe thunderstorms or tornadoes are rare, but have occurred. Tornado warnings have been posted for the city on a few occasions in the past few years, however no touchdowns have been confirmed in the city since a weak tornado hit Scarborough in the mid−1990s. A pair of dangerous F2 tornados did touchdown in neighbouring Vaughan on August 20 during the 2009 tornado season.
The tropical storm remnant of Hurricane Hazel caused 81 deaths in October 1954 due to flooding that swept homes along river banks into Lake Ontario. A sudden downburst during a strong thunderstorm was believed to have played a contributing factor in the Air France Flight 358 crash in August 2005 and just a few weeks later record-breaking intense rainfall, the worst since Hazel, deluged many areas of the city within a couple of hours resulting in record insurance claims.
On occasion, high winds knock down trees, powerlines, and localized flooding resulting from flash thunderstorms in summer or rapidly melting snow with rainfall in the colder season can overflow the storm drain network.
During the 1936 North American heat wave the highest temperature on record in Toronto of 41 °C (106 °F) were recorded on three consecutive days from July 7−July 9. The prolonged heat wave that month claimed about 200 lives from heat stroke; hundreds more drowned while attempting to cool off at a time when the city was ill equipped to handle such extreme heat.[8] The hottest month recorded, however, was July 1921, when the average maximum temperature downtown was 31.7 °C (89 °F), and a mean temperature of 26 °C (79 °F) still holds as the warmest month. At the airport, the highest monthly maximum average was 31.2 °C (88 °F) in July 1955.
The coldest minimum temperature of −33 °C (−27 °F) was recorded on January 10, 1859. The coldest temperature recorded at Toronto Pearson International Airport was −31.3 °C (−24.3 °F) on January 4, 1981, and the coldest windchill recorded was −44.7 (−48.5) on the same day.[3][4] The coldest month overall: at the airport January 1994, averaging −12.4 °C (10 °F); downtown February 1875 averaged −12.6 °C (9 °F). Winter cold snaps pose a danger as they often come with high winds, leaving the city's homeless population very prone to frostbite and hypothermia.
Statistics
Climate data for The Annex, Toronto Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Record high °C (°F) 16.1
(61.0)14.4
(57.9)26.7
(80.1)32.2
(90.0)34.4
(93.9)36.7
(98.1)40.6
(105.1)38.9
(102.0)37.8
(100.0)30.0
(86.0)23.9
(75.0)19.9
(67.8)40.6
(105.1)Average high °C (°F) −1.1
(30.0)−0.2
(31.6)4.6
(40.3)11.3
(52.3)18.5
(65.3)23.5
(74.3)26.4
(79.5)25.3
(77.5)20.7
(69.3)13.8
(56.8)7.4
(45.3)1.8
(35.2)12.7 Average low °C (°F) −7.3
(18.9)−6.3
(20.7)−2
(28)3.8
(38.8)9.9
(49.8)14.8
(58.6)17.9
(64.2)17.3
(63.1)13.2
(55.8)7.3
(45.1)2.2
(36.0)−3.7
(25.3)5.6 Record low °C (°F) −32.8
(−27.0)−31.7
(−25.1)−26.7
(−16.1)−15
(5)−3.9
(25.0)−2.2
(28.0)3.9
(39.0)4.4
(39.9)−2.2
(28.0)−8.9
(16.0)−20.6
(−5.1)−30
(−22)−32.8
(−27.0)Precipitation mm (inches) 61.2
(2.409)50.5
(1.988)66.1
(2.602)69.6
(2.74)73.3
(2.886)71.5
(2.815)67.5
(2.657)79.6
(3.134)83.4
(3.283)64.7
(2.547)75.7
(2.98)71.0
(2.795)834.0
(32.835)Rainfall mm (inches) 29.2
(1.15)26.2
(1.031)42.0
(1.654)63.2
(2.488)73.3
(2.886)71.5
(2.815)67.5
(2.657)79.6
(3.134)83.4
(3.283)64.7
(2.547)67.3
(2.65)41.9
(1.65)709.8
(27.945)Snowfall cm (inches) 38.2
(15.04)26.6
(10.47)22.0
(8.66)6.0
(2.36)0
(0)0
(0)0
(0)0
(0)0
(0)0.1
(0.04)8.1
(3.19)32.2
(12.68)133.1
(52.4)Avg. precipitation days (≥ 0.2 mm) 15.3 11.7 12.7 12.1 12.2 11.1 10.3 10.5 10.6 11.4 12.7 14.5 145.1 Avg. rainy days (≥ 0.2 mm) 5.2 4.6 8.0 10.9 12.2 11.1 10.3 10.5 10.6 11.4 10.6 7.4 112.8 Avg. snowy days (≥ 0.2 cm) 12.0 8.7 6.4 2.2 0 0 0 0 0 .07 3.2 9.5 42.0 Sunshine hours 88.3 110.3 156.3 185.4 229.1 256.2 276.2 241.3 188.0 148.4 83.6 74.7 2,037.6 Source: Environment Canada [2] Climate data for Toronto Pearson International Airport 1971−2000 Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Record high °C (°F) 16.7
(62.1)14.9
(58.8)25.6
(78.1)31.1
(88.0)34.4
(93.9)36.7
(98.1)37.6
(99.7)38.3
(100.9)36.7
(98.1)30.6
(87.1)25.0
(77.0)20.0
(68.0)38.3
(100.9)Average high °C (°F) −2.1
(28.2)−1.1
(30.0)4.1
(39.4)11.5
(52.7)18.8
(65.8)23.7
(74.7)26.8
(80.2)25.6
(78.1)21.0
(69.8)13.9
(57.0)7.0
(44.6)0.9
(33.6)12.5 Daily mean °C (°F) −6.3
(20.7)−5.4
(22.3)−0.4
(31.3)6.3
(43.3)12.9
(55.2)17.8
(64.0)20.8
(69.4)19.9
(67.8)15.3
(59.5)8.9
(48.0)3.2
(37.8)−2.9
(26.8)7.5 Average low °C (°F) −10.5
(13.1)−9.7
(14.5)−5
(23)1.0
(33.8)6.9
(44.4)11.9
(53.4)14.8
(58.6)14.0
(57.2)9.6
(49.3)3.9
(39.0)−0.7
(30.7)−6.7
(19.9)2.5 Record low °C (°F) −31.3
(−24.3)−31.1
(−24.0)−28.9
(−20.0)−17.2
(1.0)−5.6
(21.9)0.6
(33.1)3.9
(39.0)1.1
(34.0)−3.9
(25.0)−8.3
(17.1)−18.3
(−0.9)−31.1
(−24.0)−31.3
(−24.3)Wind chill −44.7 −38.9 −32.6 −25.4 −9.5 −2.6 2.5 −0.9 −8 −13.5 −25.4 −38.5 −44.7 Precipitation mm (inches) 52.2
(2.055)42.6
(1.677)57.1
(2.248)68.4
(2.693)72.5
(2.854)74.2
(2.921)74.4
(2.929)79.6
(3.134)77.5
(3.051)64.1
(2.524)69.3
(2.728)60.9
(2.398)792.7
(31.209)Rainfall mm (inches) 24.9
(0.98)22.3
(0.878)36.7
(1.445)62.4
(2.457)72.4
(2.85)74.2
(2.921)74.4
(2.929)79.6
(3.134)77.5
(3.051)63.4
(2.496)62.0
(2.441)34.7
(1.366)684.6
(26.953)Snowfall cm (inches) 31.1
(12.24)22.1
(8.7)19.2
(7.56)5.7
(2.24)0.1
(0.04)0.0
(0)0.0
(0)0.0
(0)0.0
(0)0.5
(0.2)7.6
(2.99)29.2
(11.5)115.4
(45.43)Source no. 1: Environment Canada[4] Source no. 2: Extremes from 1937−2002, all other data from 1971−2000[9] References
- ^ Trees on Private Property
- ^ a b c "Canadian Climate Normals 1971-2000". Environment Canada. http://www.climate.weatheroffice.ec.gc.ca/climate_normals/results_e.html?Province=ALL&StationName=toronto&SearchType=BeginsWith&LocateBy=Province&Proximity=25&ProximityFrom=City&StationNumber=&IDType=MSC&CityName=&ParkName=&LatitudeDegrees=&LatitudeMinutes=&LongitudeDegrees=&LongitudeMinutes=&NormalsClass=A&SelNormals=&StnId=5051&. Retrieved 2009-08-07.
- ^ a b "Canada's Wind Chill Index". Environment Canada. 2005-01-04. http://www.pnr-rpn.ec.gc.ca/air/wintersevere/windchill.en.html. Retrieved 2009-02-16. "The wind chill is expressed in temperature-like units, but because it is not the actual air temperature, it is given without the degree sign."
- ^ a b c "Canadian Climate Normals 1971-2000, Toronto Pearson International Airport". Environment Canada. http://www.climate.weatheroffice.ec.gc.ca/climate_normals/results_e.html?Province=ALL&StationName=Toronto&SearchType=BeginsWith&LocateBy=Province&Proximity=25&ProximityFrom=City&StationNumber=&IDType=MSC&CityName=&ParkName=&LatitudeDegrees=&LatitudeMinutes=&LongitudeDegrees=&LongitudeMinutes=&NormalsClass=A&SelNormals=&StnId=5097&.
- ^ http://www.ec.gc.ca/default.asp?lang=En&n=714D9AAE-1&news=980B4916-73ED-40B2-91CD-12B0A270C7CE
- ^ Lake Breeze Weather
- ^ Impact of urbanization on the climate of Toronto, Ontario, Canada
- ^ The Worst Heatwave In T.O. History
- ^ "Calculation Information for 1971 to 2000 Canadian Normals Data, Toronto Pearson International Airport". Environment Canada. http://www.climate.weatheroffice.ec.gc.ca/climate_normals/station_metadata_e.html?Province=ALL&StationName=Toronto&SearchType=BeginsWith&LocateBy=Province&Proximity=25&ProximityFrom=City&StationNumber=&IDType=MSC&CityName=&ParkName=&LatitudeDegrees=&LatitudeMinutes=&LongitudeDegrees=&LongitudeMinutes=&NormalsClass=A&SelNormals=&StnId=5097&.
Categories:- Geography of Toronto
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