Frequently Asked Questions

A Snow Day Predictor estimates the probability that schools will be closed tomorrow due to winter weather — including heavy snowfall, ice, extreme cold, or dangerous wind chills. It uses live weather forecast data and a multi-factor model to generate a probability score from 0–100%, along with a plain-language explanation of the key drivers.

The model factors in expected snowfall accumulation, overnight low temperatures, wind chill, precipitation probability, and regional closure patterns. These inputs are weighted and combined to produce a score. A southern city may close for 1–2 inches of snow; a northern city accustomed to heavy winters needs significantly more. See our Data Sources page for the full breakdown.

Weather forecasts are updated multiple times per day as new atmospheric observations arrive. A storm that appeared to miss your area at noon may be more likely to hit by evening as the forecast sharpens. We recommend checking back in the late afternoon for the most accurate overnight and next-morning prediction.

The score (0–100%) reflects the modeled likelihood of a school closure given current weather forecasts and regional norms. A score of 80% means conditions are strongly aligned with historical closure patterns for your area. It does not mean school is definitely cancelled — only that the weather conditions make it likely. Always check official district announcements.

Predictions are estimates based on live forecast data and regional patterns. Accuracy depends heavily on the quality of the underlying weather forecast, which improves as the event approaches. Short-range forecasts (12–24 hours) are generally more reliable than longer-range ones. We do not track or publish a formal accuracy rate, as closure decisions vary too widely by district.

No. Snow Day Calculation is an independent, unofficial educational tool. School closure decisions are made by individual districts based on many factors — road conditions, bus availability, staff safety, and local policies — that our model cannot fully account for. Always check your district's official website, app, or emergency notification system for confirmed closure information.

Yes. The calculator supports cities and postal codes in both the USA and Canada. The regional factor in the model is calibrated to account for typical closure thresholds in different climate zones. Coverage outside North America is not currently available.

Predictions are powered by the Open-Meteo API, which aggregates forecast data from leading numerical weather models. Variables used include forecasted snowfall totals, overnight temperature lows, wind chill, and precipitation probability. See the Weather APIs and Data Sources pages for more detail.

No. Your location — whether entered as text or from your device's GPS — is used only to fetch weather data for the current session. It is not stored on our servers, not logged, and not linked to any identifier. See our Privacy Policy for full details.

Yes, completely free. No account required, no signup, no ads on the calculator itself. The tool is built and maintained by an individual developer as a public resource for families and students.