A snow day calculator estimates the probability of a school or workplace closure by using weather forecasts, historical closure data, predicted snowfall, temperature levels, and sometimes local regulations. Accuracy: • More reliable than guessing because it is based on actual weather and past data. • Not completely accurate, as weather forecasts can change and closure decisions depend on local factors such as road conditions, staff availability, and safety policies. • Most effective when used 1–3 days in advance; accuracy decreases for longer-term predictions.