Here’s a clean and natural rephrased version:
Snow day calculator apps now play an important role for families by helping them predict the possibility of school closures. This article outlines what a snow day means, why schools decide to shut down, and how those choices are determined. A snow day is announced when severe winter conditions make it unsafe for students and staff to attend school. Heavy snowfall, icy or hazardous roads, extreme cold, and blizzard conditions are typical causes of closures. When a snow day is declared, classes are canceled to keep students safe at home rather than commuting in dangerous weather.