Alliston Snow Day Predictor – Simcoe County DSB and Simcoe Muskoka Catholic
Will Tomorrow Be a Snow Day?
Canada's most accurate snow day predictor
Alliston, in New Tecumseth at the southwestern edge of Simcoe County, shares the Simcoe County District School Board (SCDSB) with Barrie and the rest of the county. The town averages approximately 180–220 cm of snow per year and sits in an area exposed to both Georgian Bay lake-effect snow and open-country drifting. As a smaller rural community, Alliston’s bus routes across exposed farmland are a central factor in SCDSB closure decisions.
Will Alliston schools be closed tomorrow? Enter your city in the predictor above for tonight’s closure probability, updated hourly from Environment Canada data. Always confirm with your school board’s official channels before making plans.
Alliston School Boards – Who Decides Closures
- Simcoe County District School Board (SCDSB) – Alliston, Barrie, Orillia, Bradford, and all of Simcoe County. scdsb.on.ca | Announces: by 6:00 AM | Radio: 96.7 KICX FM, Jewel 88.5 | Twitter/X: @SCDSBSchools
- Simcoe Muskoka Catholic District School Board (SMCDSB) – Catholic board for Alliston and Simcoe County. smcdsb.on.ca | Announces: by 6:00-6:30 AM | Twitter/X: @SMCDSB
Alliston Snow Day Triggers – What Closes Schools Here
Alliston’s closures are driven by:
- Georgian Bay lake-effect: Southwestern Simcoe County catches lake-effect snowbands, particularly in northwest wind setups.
- Open-country drifting: Alliston’s surrounding flat farmland produces significant blowing and drifting snow that closes rural bus routes even without new snowfall.
- Regional storms: Major systems affecting the northern GTA and Simcoe County deliver significant snowfall to Alliston.
How Often Do Alliston Schools Close?
As part of the SCDSB, Alliston schools close approximately 6–10 days per year. Rural bus cancellations around Alliston are frequent due to drifting on exposed county roads. November through February are peak months.
See Also – Nearby Predictors and Guides
Explore the Ontario Snow Day Predictor for all school boards in the province, or check nearby cities:
Related guides:
Frequently Asked Questions – Alliston Snow Days
Which school board and bus zone does the Alliston predictor track?
The predictor calculates data for the Simcoe County District School Board (SCDSB) and the Simcoe County Catholic District School Board. For school bus routing, Alliston is located inside the South Zone (Zone 3) of the Simcoe County Student Transportation Consortium (SCSTC).
Why does the Alliston predictor spike when the streets inside the town look clear?
Alliston shares its transit zone with open rural areas across New Tecumseth, Essie, and Bradford. The predictor calculates risk for the whole zone, meaning that heavy drifting snow, low visibility, or black ice on rural country lines outside town limits can easily cancel buses for Alliston schools even if downtown streets are salted and clear.
How much snow does it take to trigger a bus cancellation on the Alliston predictor?
There is no exact centimeter rule, but the predictor’s algorithm spikes sharply when a weather warning forecasts 10 to 15 cm of rapid accumulation right before the morning commute. The predictor weighs freezing rain and ice buildup on rural regional roads much heavier than standard, dry snowfall.
If the Alliston predictor hits 100% and buses are cancelled, are schools closed?
No, schools almost always remain open for walking students and staff even when buses are cancelled. However, a high percentage helps parents plan for “inclement weather days” where regular curriculum lessons are paused, and no new graded work, tests, or exams take place.
When is the best time to check the Alliston snow day predictor for maximum accuracy?
The highest accuracy window is between 5:00 AM and 5:30 AM on the morning of a storm. While checking at 9:00 PM the night before provides a helpful baseline estimate, overnight shifts in lake-effect snow bands off Georgian Bay heavily alter the final data models right before the official SCSTC announcement at 6:00 AM.