The Prediction Algorithm
Our snow day predictor uses a weighted scoring system that analyzes multiple real-time weather data points to calculate a probability score from 0 to 100%. The algorithm was developed by analyzing thousands of historical school closure decisions across different regions and school districts.
Each weather factor contributes a different weight to the final score based on its historical correlation with school closures. The result is a reliable probability estimate — not a guarantee — but a well-informed prediction.
Weather Factors We Analyze
🌨️ Snowfall Amount
Total snowfall is the single biggest factor. Even 1–2 inches can cause delays, while 4+ inches typically results in full closures. We analyze both current accumulation and forecast amounts.
Weight: Very High🌡️ Temperature
Temperatures at or below 20°F significantly increase closure probability, especially when combined with wind. Extreme cold alone can cause cancellations in some districts.
Weight: High💨 Wind Speed
High winds create dangerous wind chills and reduce visibility via blowing snow. Winds above 25 mph significantly impact school decisions, especially in open rural areas.
Weight: Medium-High🥶 Wind Chill / Feels Like
The "feels like" temperature accounts for wind chill and humidity effects. Temperatures that feel below 0°F are a major safety concern for students waiting at bus stops.
Weight: Medium-High💧 Humidity
High humidity combined with near-freezing temperatures can lead to freezing rain or ice — often more dangerous than snow. Humidity above 85% near freezing temperatures increases risk.
Weight: Medium📅 24-Hour Forecast
We look ahead at the overnight and early morning forecast, since most school closure decisions are made between 4–6 AM. Predicted overnight snowfall heavily influences our score.
Weight: HighSchool Type Adjustments
Different types of schools have different thresholds for closure:
- Public Schools — Most conservative; most likely to cancel for moderate weather conditions. Base prediction score applies.
- Private Schools — Slightly less likely to cancel than public schools; prediction is reduced by ~25%.
- Colleges & Universities — Very rarely close; only in truly extreme conditions. Prediction is reduced by ~45%.
Accuracy
Our snow day calculator achieves approximately 75–80% accuracy for predictions with a probability score above 70%. Algorithm calibrated against thousands of historical North American school closure events.
Our prediction algorithm has been calibrated against thousands of historical school closure events. Here's what to expect:
- 90%+ probability — School closure is almost certain. Pack your sleds!
- 70–89% probability — Very likely to cancel. Prepare for a day off.
- 50–69% probability — A coin flip. Monitor your school's social media and local news.
- 30–49% probability — Unlikely but possible. Check again in the morning.
- Below 30% — School will almost certainly be in session. Do your homework!
Note: Our algorithm is a prediction tool, not a guarantee. Local factors such as road conditions, district policies, and superintendent decisions can always affect the final outcome.
About Snow Day Tracker
Snow Day Tracker was built by a team of weather enthusiasts and software developers passionate about helping students, parents, and educators plan ahead for winter weather. Our prediction algorithm has been refined over time using thousands of historical school closure records across the United States and Canada, and is updated regularly to improve accuracy.
We use live weather forecast data from Open-Meteo, a free and open-source weather API providing high-resolution forecast data for locations across North America.
Have questions or feedback? Contact us here.
Frequently Asked Questions
How accurate is the snow day predictor?
Our algorithm is accurate roughly 75–80% of the time when the probability is above 70%. Weather forecasting is inherently uncertain, and local school board decisions involve many factors beyond weather alone.
How often is the weather data updated?
Weather data is pulled live from the Open-Meteo forecast API at the time you submit your ZIP code. Each prediction uses the most current available data for your location.
Why is my prediction different from my friend's nearby?
Weather can vary significantly even within a few miles, especially for snowfall. Different ZIP codes pull different weather station data, which can lead to different predictions even in adjacent neighborhoods.
Does the school type really matter?
Yes! Public schools tend to be more cautious about closures than private schools, and colleges almost never close for weather. Our algorithm adjusts the probability based on the type of institution you select.
Can I use this for Canadian schools?
Yes! We support Canadian postal codes (format: A1A 1A1). The algorithm accounts for typical Canadian weather patterns and school districts that may have different closure thresholds.
When should I check the predictor for best results?
For the most relevant prediction, check between 8 PM and midnight the night before. That's when the most accurate overnight forecast data is available and when most school closure decisions begin to be made.