Summer arrives in force in Tam O'Shanter-Sullivan, hotter than in 91% of Canadian towns
Midwinter brings lows of about −10.1°C. The gap between a January night and a July afternoon is 37°C. Frost is rarer than in 70% of Canadian towns: about 145 nights a year drop below freezing. Comfortable outdoor weather, highs of 22–26°C, belongs to June, August and September.
Read at Toronto Buttonville (Airport), 10 km north-west: ECCC’s normals for 1991–2020.
A year in Tam O'Shanter-Sullivan at a glance
Each month’s typical high and low, in °C.
What stands out about Tam O'Shanter-Sullivan’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Tam O'Shanter-Sullivan feels like
Each season’s and each month’s usual high and low, 1991–2020.
Frost on 145 days, 20°C on 126
The frost season runs October to May, and January freezes nearly every night. Some 6 nights a year drop under −20°C.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
Rain and melted snow: about 862 mm a year
The most falls in June, the least in February. On about 113 days a year, 1 mm or more falls.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
Snowfall: about 146 cm in a normal year
Expect snow from November to April, with about 40 cm in January, the snowiest month.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Tam O'Shanter-Sullivan
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
Every day colder than 18°C on average adds its gap in degrees to the year’s heating total. Homes here need less heating than 74% of Canadian towns.
Living with Tam O'Shanter-Sullivan’s climate
What the normals mean for a garden, a day outside and the depth of winter.
On average the last spring frost comes around 3 May and the first autumn frost around 13 October: about 161 frost-free days between.
Plan time outside for Jun, Aug and Sep: highs of 17–27°C and nights no colder than 8°C.
Parks & trails →Roughly 22 days a year feel colder than −20 in the wind.
Summer brings about 55 days when the humidex passes 30.
Storms, floods and heat waves sit outside these normals; Tam O'Shanter-Sullivan’s hazards page covers them.
Flood & hazards →ECCC’s normals location: Toronto Buttonville (Airport)
ECCC builds the Toronto Buttonville (Airport) normals from 3 stations’ records over 1991–2020, joined where one replaced another.
| Distance from the town | 10 km north-west |
| Station altitude | 198 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Coldest reading, 1991–2020 | −35.2°C |
| Hottest reading, 1991–2020 | 37.8°C |
| Average wind | 12.2 km/h on average, most often from the north |
| Next-nearest location | Toronto (City), 15 km |
How Tam O'Shanter-Sullivan compares
Compared with 2,611 towns and neighbourhoods of 2,500 or more across Canada; the dots mark the other normals locations in Ontario.
Nearby towns’ climate
Nearby places read from a different ECCC location (places on Tam O'Shanter-Sullivan’s own would show the same figures). Distances here run 10–24 km: that is how far the nearest places with figures are from Tam O'Shanter-Sullivan.
Tam O'Shanter-Sullivan weather by month
Average daily high and low, mean temperature, rain and snow (as water) and snowfall by month, 1991–2020.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −1.7°C | −10.1°C | −6.0°C | 64 mm | 40 cm |
| February | −1.0°C | −10.1°C | −5.6°C | 51 mm | 34 cm |
| March | 4.6°C | −5.0°C | −0.2°C | 52 mm | 20 cm |
| April | 11.8°C | 1.2°C | 6.5°C | 79 mm | 7 cm |
| May | 19.3°C | 7.4°C | 13.4°C | 80 mm | under 1 cm |
| June | 24.6°C | 13.0°C | 18.8°C | 87 mm | 0 cm |
| July | 27.3°C | 15.6°C | 21.5°C | 85 mm | 0 cm |
| August | 26.3°C | 14.8°C | 20.6°C | 72 mm | 0 cm |
| September | 21.9°C | 10.4°C | 16.2°C | 83 mm | 0 cm |
| October | 14.3°C | 4.3°C | 9.4°C | 71 mm | 1 cm |
| November | 7.4°C | −0.8°C | 3.3°C | 77 mm | 12 cm |
| December | 1.5°C | −5.8°C | −2.2°C | 63 mm | 33 cm |
| Year | 13.0°C | 2.9°C | 8.0°C | 862 mm | 146 cm |
January strays furthest from its normal year to year, by 3.1°C; June the least
Bars run from each month’s record low to its record high since 1991. March spans the most, from −25.6°C (2003) to 26.3°C (2012).
Where Tam O'Shanter-Sullivan’s numbers come from
Averages over 30 years, not a forecast.
- Normals: ECCC’s normals for Toronto Buttonville (Airport), 1991–2020, chosen as the nearest location with a full temperature record.
- Comparisons: the towns and neighbourhoods of 2,500+ across Canada, each on its nearest normals location, without the city totals or the reserves.
- Not on this page: sunshine, absent from every 1991–2020 location, and an altitude correction, for want of the town’s own elevation.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Tam O'Shanter-Sullivan’s climate
How warm does Tam O'Shanter-Sullivan get in summer?
Of all twelve months, July has the warmest afternoons, about 27.3°C.
How cold does Tam O'Shanter-Sullivan get in winter?
Deep winter means January, when nights average −10.1°C.
How much rain and snow does Tam O'Shanter-Sullivan get?
Measured as water, a year brings 862 mm: 87 mm in June, the wettest month, and 51 mm in February, the driest.
How long does snow stay on the ground?
There is 1 cm of snow or more on the ground on roughly 76 days a year.
Are these figures for Tam O'Shanter-Sullivan itself?
Nearly: Toronto Buttonville (Airport), the location behind them, sits just beyond Tam O'Shanter-Sullivan’s boundary.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Tam O'Shanter-Sullivan →
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).