Frequently Asked Questions
How the snow day predictor works, what the probability scores mean, and how school board calibration affects predictions.
How accurate is the snow day predictor?
snowdayprediction.ca achieves 85 to 92% accuracy for major storm events involving 15cm or more of overnight snowfall or active freezing rain warnings. For marginal events of 5 to 10cm with mixed precipitation, accuracy is 70 to 75%. Accuracy is highest when checked at 5am after the overnight forecast has fully updated and before school board announcements.
How does the snow day predictor work?
The predictor pulls live weather data from Environment Canada every 30 minutes and runs a 9-variable scoring algorithm calibrated to the specific school board covering your city. Variables include overnight snowfall accumulation, precipitation type, wind speed, visibility forecast, active Environment Canada alerts, and a board-specific closure multiplier built from historical closure data. Full methodology details are available on the How It Works page.
When should I check the snow day predictor?
Check at 9pm for an early read to help plan backup childcare arrangements. A score above 70% at 9pm warrants preparation. Check again at 5am for the most accurate pre-announcement probability — this is when transportation assessors are actively driving routes and bus operators are making cancellation decisions. Most Ontario school boards announce by 6am.
Why does the predictor give different scores for different cities?
Each school board has a different closure threshold, geographic footprint, and historical closure frequency. Simcoe County District School Board closes 12 to 15 times per year while Toronto District School Board closes 3 to 5 times per year. The same storm produces different probability scores because the boards genuinely behave differently — board calibration is the core feature that separates snowdayprediction.ca from generic weather forecasts.
Is snowdayprediction.ca an official source?
No. snowdayprediction.ca is a probability tool, not an official source. School closure decisions are made exclusively by school boards and announced on board websites, board Twitter accounts, and local radio stations. Always verify closures through official school board sources before making decisions based on a prediction.
Does the predictor work for all Canadian cities?
The search tool accepts any Canadian city and returns a weather-based probability score. Dedicated city pages with full school board calibration are currently live for Ontario cities including Toronto, Ottawa, Hamilton, Kitchener, London, Barrie, and Guelph. More cities across Ontario and other provinces are added regularly.
What is the difference between the 9pm and 5am predictions?
The 9pm prediction reflects the evening forecast — reliable for major storms but subject to overnight forecast changes. The 5am prediction incorporates the fully updated overnight forecast, any new Environment Canada alerts issued overnight, and aligns with the window when transportation assessors are actively reporting road conditions. The 5am score is consistently more accurate than the 9pm score for marginal events.
Why does my city show a low probability even though it is snowing?
The predictor calculates closure probability based on overnight accumulation forecasts — specifically the 10pm to 6am window that transportation assessors evaluate. Current snowfall during the day does not directly affect the following morning's score unless the storm continues overnight. Road clearing during the afternoon and evening also reduces closure probability for the following morning.
Does snowdayprediction.ca collect my location data?
No. The prediction tool only uses the city name you type into the search field. No GPS location data, IP-based location tracking, or location permissions are used or requested. The city input is used solely to return a weather-based probability score and is not stored.
How do I report incorrect school board information?
Email contact@snowdayprediction.ca with the city name, the incorrect information, and the correct source. Data corrections are reviewed and applied promptly. School board boundary information, closure thresholds, and contact details are updated regularly as boards make changes.
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