Geography

Main article: Geography of Mississauga Overview map of Mississauga, including neighbourhoods, land use patterns, and transport corridors.

Mississauga covers 288.42 square kilometres (111.36 sq mi) of land, fronting 13 kilometres (8.1 mi) of shoreline on Lake Ontario.

Mississauga is bounded by Oakville and Milton to the west/southwest, Brampton to the north, Toronto to the east, and Lake Ontario to the south/south-east. Halton Hills borders Mississauga's north-west corner. With the exception of the southeast border with Toronto (Etobicoke Creek), Mississauga shares a land border with all previous mentioned municipalities.

Two major river valleys feed into the lake. The Credit River is by far the longest with the heaviest flow, it divides the western side of Mississauga from the central/eastern portions and enters the lake at the Port Credit harbour. The indented, mostly forested valley was inhabited by first nation peoples long before European exploration of the area. The valley is protected and maintained by the Credit Valley Conservation Authority (CVCA).

Etobicoke Creek forms part of the eastern border of Mississauga with the city of Toronto. North of there it passes through the western limits of Pearson Airport. There have been two aviation accidents, in 1978 and 2005 where aircraft overshot the runaway and slid into the Etobicoke creek banks. In 1954, heavy flooding resulted in some homes along the riverbank being swept into the lake after heavy rains from Hurricane Hazel. Since that storm, houses are no longer constructed along this floodplain. This creek and its tributaries are administered by the Toronto and Region Conservation Authority (TRCA).

Most land in Mississauga drains to either of the two main river systems, with the exception of the smaller Mary Fix and Cooksville Creeks which run roughly through the center of Mississauga entering the lake near Port Credit. Some small streams and reservoirs are part of the Sixteen Mile Creek system in the far north-west corner of the city, but these drain toward the lake in neighbouring Milton and Oakville.

The shoreline of former Glacial Lake Iroquois roughly follows the Dundas Street alignment, although it is not noticeable in some places but is more prominent in others, such as the site of the former brickyard (Shoreline Dr. near Mavis Rd.), the ancient shoreline promenteau affords a clear view of downtown Toronto and Lake Ontario on clear days. The land in Mississauga in ranges from a maximum elevation of 214m (699 ft) ASL in the far western corner, near the Hwy. 407/401 junction, to a minimun elevation at the Lake Ontario shore of 76 m (249 ft) ASL.

Apart from the embankments of Credit River valley, it tributaries and the Iroquois shoreline, the only noticeable hills in Mississauga are actually part of the former Britannia Landfill, now a golf course on Terry Fox Drive.

Climate

The climate of Mississauga is officially represented by Pearson International Airport but because of its topography and large surface area conditions can differ depending on location: fog tends to be more common along the lakeshore and in the Credit River Valley at certain times of year, particularly during the spring and autumn.

During snowfalls when temperatures hover close to freezing, northern parts of the city, such as around Derry Road away from warmer Lake Ontario usually get more snow that sticks to the ground because of the lower temperatures. The reverse occurs when a strong storm approaches from the south kicking up lake effect snow, bringing higher snowfall totals to south Mississauga. The city usually experiences 8 months of snow free weather however there is the odd occurrence where snow does fall either in November or April. The Port Credit and Lakeview areas have a micro-climate more affected by the proximity of the open lake, warming winter temperatures as a result but it can be sharply cooler on spring and summer afternoons, this can also be the case in Clarkson, but with much less consistentcy.

Summer thunderstorms are common, most are not severe but can occasionally bring violent winds. The last known tornado to cause significant damage touched down on July 7, 1985, when an F1 rated tornado struck an industrial park in the Meadowvale area (Argentia Road), heavily damaging some buildings and some parked tractor trailers. A relatively strong tornado tore a path across Mississauga (then part of Toronto Township) on June 24, 1923, cutting a swath from present-day Meadowvale to near Cooksville, killing 4 people and causing massive property damage in a time when most of Mississauga was still rural farmland dotted with fruit orchards.

Climate data for Lester B. Pearson International Airport 1981−2010 (North Mississauga) Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Record high Humidex 19.0 14.8 29.2 37.9 42.6 45.0 50.3 46.6 48.0 39.1 28.6 23.9 50.3 Record high °C (°F) 17.6 (63.7) 14.9 (58.8) 25.6 (78.1) 31.1 (88) 34.4 (93.9) 36.7 (98.1) 37.6 (99.7) 38.3 (100.9) 36.7 (98.1) 31.6 (88.9) 25.0 (77) 20.0 (68) 38.3 (100.9) Average high °C (°F) −1.5 (29.3) −0.4 (31.3) 4.6 (40.3) 12.2 (54) 18.8 (65.8) 24.2 (75.6) 27.1 (80.8) 26.0 (78.8) 21.6 (70.9) 14.3 (57.7) 7.6 (45.7) 1.4 (34.5) 13.0 (55.4) Daily mean °C (°F) −5.5 (22.1) −4.5 (23.9) −0.1 (31.8) 7.1 (44.8) 13.1 (55.6) 18.6 (65.5) 21.2 (70.2) 20.6 (69.1) 16.2 (61.2) 9.5 (49.1) 3.7 (38.7) −2.2 (28) 8.2 (46.8) Average low °C (°F) −9.4 (15.1) −8.7 (16.3) −4.5 (23.9) 1.9 (35.4) 7.4 (45.3) 13.0 (55.4) 15.8 (60.4) 15.1 (59.2) 10.8 (51.4) 4.6 (40.3) −0.2 (31.6) −5.8 (21.6) 3.3 (37.9) Record low °C (°F) −31.3 (−24.3) −31.1 (−24) −28.9 (−20) −17.2 (1) −5.6 (21.9) 0.6 (33.1) 3.9 (39) 1.1 (34) −3.9 (25) −8.3 (17.1) −18.3 (−0.9) −31.1 (−24) −31.3 (−24.3) Wind chill −44.7 −38.9 −36.2 −25.4 −9.5 0.0 0.0 0.0 −8.0 −13.5 −25.4 −38.5 −44.7 Precipitation mm (inches) 51.8 (2.039) 47.7 (1.878) 49.8 (1.961) 68.5 (2.697) 74.3 (2.925) 71.5 (2.815) 75.7 (2.98) 78.1 (3.075) 74.5 (2.933) 61.1 (2.406) 75.1 (2.957) 57.9 (2.28) 785.9 (30.941) Rainfall mm (inches) 25.1 (0.988) 24.3 (0.957) 32.6 (1.283) 63.0 (2.48) 74.3 (2.925) 71.5 (2.815) 75.7 (2.98) 78.1 (3.075) 74.5 (2.933) 60.6 (2.386) 68.0 (2.677) 34.0 (1.339) 681.6 (26.835) Snowfall cm (inches) 29.5 (11.61) 24.0 (9.45) 17.7 (6.97) 4.5 (1.77) 0.02 (0.008) 0.0 (0) 0.0 (0) 0.0 (0) 0.0 (0) 0.4 (0.16) 7.5 (2.95) 24.9 (9.8) 108.5 (42.72) Avg. precipitation days (≥ 0.2 mm) 15.1 11.6 12.4 12.5 12.5 10.8 10.4 10.2 10.5 12.1 13.2 14.8 145.9 Avg. rainy days (≥ 0.2 mm) 5.4 4.6 7.4 11.3 12.5 10.8 10.4 10.2 10.5 12.0 11.0 7.1 113.2 Avg. snowy days (≥ 0.2 cm) 12.1 9.4 6.8 2.4 0.03 0.0 0.0 0.0 0.0 0.3 3.4 10.0 44.4  % humidity 80.8 79.3 78.1 75.4 77.2 79.8 81.9 85.7 87.4 85.2 83.3 81.8 81.3 Mean monthly sunshine hours 79.7 112.2 159.4 204.4 228.2 249.7 294.4 274.5 215.7 163.7 94.2 86.2 2,161.4 Percent possible sunshine 27.6 38.0 43.2 50.8 50.1 54.1 63.0 63.4 57.4 47.8 32.0 30.9 46.5 Source: Environment Canada (all extremes 1937-present)