Afternoon heat in Thornlea beats that of 91% of Canadian towns
Midwinter brings lows of about −10.1°C. Frost is rarer than in 70% of Canadian towns: about 145 nights a year drop below freezing. Winter and summer sit 37°C apart. Plan time outside for June, August and September, when highs sit at 22–26°C.
Borrowed figures: Thornlea has no normals station, so these come from Toronto Buttonville (Airport), 4.2 km north-east.
A year in Thornlea at a glance
Each month’s typical high and low, in °C.
What stands out about Thornlea’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Thornlea feels like
Seasons and months as ECCC’s 1991–2020 normals give them: a typical day’s high and low.
145 frost days and 126 days above 20°C a year
From October to May frost is routine, and in January it comes on almost 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
862 mm of precipitation in a typical year
June is the wettest month and February the driest. Some 113 days a year see 1 mm of rain or snow or more.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
146 cm of snow in a typical year
The snow season runs November to April; January brings the most, about 40 cm.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Thornlea
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
Think of it as a year’s worth of daily shortfalls below 18°C, added up. By this count, homes here need less heating than 74% of Canadian towns.
Living with Thornlea’s climate
Gardening, time outside, winter cold and summer heat, from the 1991–2020 normals.
From about 3 May to 13 October the garden is usually clear of frost, some 161 days.
Warm afternoons without cold nights, 17–27°C and 8°C or more, mark Jun, Aug and Sep.
Parks & trails →Frostbite weather, a wind chill under −20, turns up on about 22 days a year.
Humid summer days, the humidex above 30, number about 55 a year.
Averages smooth over blizzards, ice storms, floods and heat waves; Thornlea’s hazards page covers the risks.
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 | 4.2 km north-east |
| 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), 17 km |
How Thornlea compares
Against the 2,611 Canadian towns and neighbourhoods of 2,500 or more, each read from its own normals location; the dots are the other locations those towns use in Ontario.
Nearby towns’ climate
The nearest places on a normals location of their own: those that share Thornlea’s would only repeat its figures. Thornlea has few close neighbours with figures, so the list reaches 12–29 km out.
Thornlea weather by month
Each month’s normals, 1991–2020: high, low, mean, precipitation and snowfall.
| 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 |
The month with the widest range: March, −25.6°C to 26.3°C
Two years in three, January’s average falls within 3.1°C of its normal of −6.0°C; June keeps to within 1.2°C.
Where Thornlea’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the closest ECCC location with twelve months of temperature normals, Toronto Buttonville (Airport), 1991–2020.
- Comparisons: Canada’s towns and neighbourhoods of 2,500+ (no city totals, no reserves), each through its own nearest location.
- Not on this page: hours of sunshine, missing from the 1991–2020 normals, and a height correction: the town has no elevation on file.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Thornlea’s climate
How warm does Thornlea get in summer?
Peak warmth comes in July, at about 27.3°C by mid-afternoon.
How cold does Thornlea get in winter?
On a normal January night the air drops to −10.1°C, the coldest of the year.
How much rain and snow does Thornlea get?
A normal year brings 862 mm, snow included as water: June is wettest at 87 mm, February driest at 51 mm.
How long does snow stay on the ground?
About 76 days a year have 1 cm of snow or more on the ground.
Are these figures for Thornlea itself?
Only indirectly: the readings are made at Toronto Buttonville (Airport), outside Thornlea.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Thornlea →
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).