Photo: Michael Gil · CC BY 2.0The climate in Alliston sits close to the middle of Canadian towns
A typical July afternoon reaches 26.0°C, a January night drops to −11.3°C, and 793 mm of rain and snow falls in a year. It is a dry place: less rain and snow fall here than on 65% of Canadian towns. Temperatures cover 37°C across the year, low to high. Windshields need scraping on about 155 mornings a year, the days the air reaches 0°C or below.
Borrowed figures: Alliston has no normals station, so these come from Egbert, 16 km north.
A year in Alliston at a glance
Each month’s typical high and low, in °C.
What stands out about Alliston’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Alliston feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
About 155 frosts and 114 warm days a year
The frost season runs October to May, and January freezes nearly every night. On about 9 nights a year the air falls below −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 793 mm a year
June brings the most rain and snow; February, the least. About 115 days a year bring 1 mm or more.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
About 174 cm of snow a year
Expect snow from October to April, with about 42 cm in December, the snowiest month.
Snowfall by month
Centimetres
Heating a home in Alliston
91% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
Measured against 18°C: each day’s shortfall in mean temperature, added over twelve months. Homes here need less heating than 65% of Canadian towns.
Living with Alliston’s climate
The averages read for the garden, the outdoors and the coldest and hottest days.
Between the last frost, near 16 May, and the first, near 5 October, lie about 141 frost-free days.
For long days outdoors, Jun, Jul, Aug and Sep bring highs of 17–27°C and lows of 8°C or more.
Parks & trails →A wind chill below −20 is part of about 26 days a year here.
The humidex tops 30 on about 49 days a year: muggy days to plan around.
Thirty years of averages say little about one bad storm; Alliston’s hazards page does.
Flood & hazards →ECCC’s normals location: Egbert
Behind the 1991–2020 normals for Egbert are 2 stations, which ECCC combines into one record.
| Distance from the town | 16 km north |
| Station altitude | 251 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Coldest reading, 1991–2020 | −35.5°C |
| Hottest reading, 1991–2020 | 36.5°C |
| Average wind | 11.3 km/h on average, most often from the south |
| Next-nearest location | Toronto Buttonville (Airport), 42 km |
How Alliston 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 Alliston’s own would show the same figures). Distances here run 23–29 km: that is how far the nearest places with figures are from Alliston.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Alliston Egbert | 26.0°C | −11.3°C | 793 mm |
| King 23 km · Toronto Buttonville (Airport) | 27.3°C 1.3°C warmer | −10.1°C 1.2°C milder | 862 mm |
| Bolton 25 km · Toronto Pearson (Airport) | 27.4°C 1.4°C warmer | −8.9°C 2.4°C milder | 807 mm |
| East Gwillimbury 29 km · Udora | 26.3°C about the same | −11.7°C about the same | 883 mm |
Alliston weather by month
Month by month, 1991–2020: the usual high, low and mean, the rain and snow, and the snowfall.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −2.9°C | −11.3°C | −7.2°C | 55 mm | 40 cm |
| February | −2.0°C | −10.8°C | −6.4°C | 45 mm | 33 cm |
| March | 3.2°C | −5.9°C | −1.3°C | 48 mm | 26 cm |
| April | 10.9°C | 0.3°C | 5.6°C | 62 mm | 9 cm |
| May | 18.4°C | 6.2°C | 12.3°C | 74 mm | under 1 cm |
| June | 23.4°C | 11.5°C | 17.5°C | 83 mm | 0 cm |
| July | 26.0°C | 14.2°C | 20.1°C | 78 mm | 0 cm |
| August | 25.0°C | 13.3°C | 19.2°C | 83 mm | 0 cm |
| September | 21.1°C | 9.5°C | 15.3°C | 72 mm | 0 cm |
| October | 13.6°C | 4.1°C | 8.9°C | 65 mm | 3 cm |
| November | 6.4°C | −1.1°C | 2.7°C | 72 mm | 22 cm |
| December | 0.3°C | −6.6°C | −3.2°C | 58 mm | 42 cm |
| Year | 11.9°C | 2.0°C | 7.0°C | 793 mm | 174 cm |
The month with the widest range: March, −29.0°C to 26.5°C
Two years in three, January’s average falls within 3.1°C of its normal of −7.2°C; August keeps to within 1.2°C.
Where Alliston’s numbers come from
Averages over 30 years, not a forecast.
- Normals: ECCC’s 1991–2020 Canadian Climate Normals for Egbert, the nearest location with a full year of temperatures.
- Comparisons: all Canadian places of 2,500 or more except city totals and reserves, each read the same way.
- Not on this page: sunshine, which none of ECCC’s 450 locations publishes for 1991–2020, and the town’s own height above sea level, so no figure is adjusted for altitude.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Alliston’s climate
How warm does Alliston get in summer?
In July, the warmest month, the typical high is 26.0°C.
How cold does Alliston get in winter?
On a normal January night the air drops to −11.3°C, the coldest of the year.
How much rain and snow does Alliston get?
Count on roughly 793 mm a year, heaviest in June (83 mm) and lightest in February (45 mm).
Are these figures for Alliston itself?
Not quite: they come from Egbert, the closest ECCC normals location to Alliston.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Alliston →
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).