Snow Day Calculator

Our calculator is a probability estimator based on key weather factors — not a live weather service. It gives a directional prediction, not a guarantee. Accuracy depends on how precisely you enter your local conditions. Actual school closure decisions involve road conditions, district policies, and superintendent judgment that no formula can fully capture. Think of it as a well-informed estimate rather than a definitive forecast.

As a rough guide: under 30% means school is almost certainly on, 30–50% is genuinely uncertain, 50–70% leans toward a cancellation, and above 70% means most public schools in snowy regions would likely close. Above 85% in a northern state district is a near-certainty for public schools. Private schools and colleges require much higher scores due to their higher threshold for closure.

Yes, significantly. Extremely cold temperatures (below 10°F / -12°C) can trigger school closures even with little or no snow, due to dangerous wind chill conditions that make waiting for buses unsafe. Conversely, temperatures above 35°F (2°C) mean snow is likely to melt quickly, reducing road hazards — which lowers snow day probability even if snowfall totals are significant.

Private schools often have smaller geographic footprints, meaning students and staff live closer to campus on average. They also don't run large bus fleets, which removes a major safety variable. Colleges and universities expect students to make independent decisions about whether to attend class, and most have policies that leave attendance up to individual instructors. The operational calculus is simply different from a public district managing 100 buses across rural routes.

Wind significantly amplifies the impact of snowfall through three mechanisms: drifting (moving snow from cleared areas back onto roads), reduced visibility (white-out conditions can ground buses even with modest snow totals), and wind chill (making outdoor waiting dangerous). Wind speeds above 30 mph during a snowstorm are a strong signal for closure, often even when accumulation is on the lower end.

Yes. Switch to metric units (cm / °C / km/h) using the toggle at the top of the inputs. The underlying scoring formula applies equally to Canadian conditions. Canadian school boards generally follow similar decision-making processes to US districts, though thresholds in provinces like Ontario or Quebec may be higher due to greater local experience with heavy snow. The 'public school' setting is appropriate for most Canadian public boards.

Most public school districts in the US and Canada announce cancellations between 5:00 and 7:00 AM on the day of the storm. Many districts now also announce the night before if the forecast is clear enough. Check your district's website, social media accounts, local TV news school closing lists, or sign up for automated text/email alerts — these are the fastest sources.

Our formula starts with a snowfall base score (0–98 points), then applies modifiers for temperature (−10 to +12), wind speed (0 to +15), ice/freezing rain (0 to +22), storm duration (0 to +10), timing (−5 to +10), school type (−20 to 0), and existing snow on the ground (0 to +20). The raw total is clamped to a maximum of 98% — because a guaranteed snow day doesn't exist. The factor breakdown in the results panel shows exactly how each condition contributed to your prediction.