This plain-language guide provides a transparent overview of our prediction methodology, and the data sources behind every prediction. It explains how our snow day calculator processes daily atmospheric data to determine the likelihood of a school closing in your specific area.
Our school closing calculator pulls hourly weather data directly from the NOAA National Weather Service API for all 40,000+ US ZIP codes, updating daily to reflect the latest atmospheric shifts.
For every ZIP code, we analyze a 5-day school week window (Monday–Friday). Our snow day calculator records critical variables including minimum temperature, wind chill, snowfall totals, ice accumulation, and precipitation probability. This data allows us to project both full-day closures and early dismissal scenarios.
Each weather factor is compared against local historical percentiles — calibrated separately for each month and location. For example, 3 inches of overnight snow in January in Minneapolis gets a very different closure probability than 3 inches in Atlanta in March.
While heavy snow is the primary reason for a snow day, we also calculate the impact of extreme cold, dangerous wind chills, and icy road conditions. Our algorithm mirrors the decision-making process of school administrators, weighing multiple simultaneous hazards before making a decision to close school on a snow day.
Our snow day calculator predicts a School Closure by evaluating overnight and morning weather data (the critical window before the school day begins), and assesses Early Dismissal probability by analyzing deteriorating conditions during active school hours.