This snow day calculator does not yet have a verified accuracy rate. Its percentage is a weather-based planning score, not a measured record of how often schools closed. Use it to understand forecast pressure, then check the district's announcement for the actual decision.
What the estimate is actually measuring
Our calculator converts forecast snowfall, possible icing, temperature, wind and morning timing into a consistent score. It then adjusts for broad school and area settings. The full weighting method is public, so a user can see why a result rose or fell.
The number does not represent a district's own forecast, and it is not trained on a complete history of every school system. We deliberately avoid unsupported claims such as a universal “95% accuracy” rate. Without a published, independently auditable dataset, that kind of headline is not meaningful.
Why forecasts change
Weather models are rerun as new observations arrive. A small shift in storm track can move a narrow snow band, change precipitation type or alter the timing of the heaviest period. Open-Meteo combines output from multiple national weather services into regularly updated time series, but each variable still contains uncertainty.
That is why a prediction made several days early should carry less decision weight than one made the evening before. Follow the best-time-to-check routine instead of treating the first number you see as fixed.
What the calculator cannot observe
- actual pavement temperature and untreated side roads;
- bus driver and substitute staffing;
- power, heat or water problems at a school building;
- district-specific attendance and remote-learning rules;
- the final judgment of local administrators.
Those limits are not defects to hide; they define the proper use of the tool. Learn more about the operational decision schools make and review our accuracy statement before relying on any result.
A responsible way to use the percentage
- Use an early estimate to decide whether to prepare childcare, travel or remote-learning plans.
- Recheck as the storm approaches and compare the factor breakdown—not only the final number.
- Read current weather alerts and official updates.
- Treat your district's announcement as the only authoritative closure decision.
Good uncertainty is useful. A transparent range of possibilities is more honest than a confident-looking number with no explanation.
What would demonstrate prediction accuracy?
A useful evaluation would save predictions before schools announce their decisions, then compare them with dated, linked official outcomes. It should include ordinary open days and wrong predictions as well as memorable storms. Forecasts made the evening before should be evaluated separately from morning forecasts; a later update has more information available.
Closures, delays, bus cancellations and remote-learning days also need separate outcome labels. Counting all four as a correct closure prediction would hide mistakes. Our guide to school delays and snow days explains those differences.
If a service presents a result of 70% as a calibrated probability, roughly seven out of ten comparable cases in that band should end in the stated outcome over a sufficiently large sample. That is an illustration of what calibration means, not a finding about this calculator. We have not published that validation yet, so there is no supported claim that a score of 70 here means schools actually close 70% of the time.
