* The amount of snow on the ground: A heavy, wet snow of 2 inches might be more disruptive than 4 inches of light, fluffy snow.
* The rate of snowfall: A steady, heavy snowfall makes roads hazardous even with a smaller accumulation than a light snowfall that stopped hours ago.
* The temperature: Freezing temperatures can make roads icy even with minimal snow accumulation.
* Road conditions: How well the roads are plowed and salted is a major factor. Rural areas often close schools sooner than urban areas with better snow removal.
* School district policies: Each school district has its own specific policies and thresholds. Some might close with minimal snow, others might wait for significant accumulation and icy conditions.
* Transportation: The ability of buses to safely navigate the roads is paramount.
In short, there's no magic number. You need to check your local school district's website or social media channels for announcements regarding school closures due to inclement weather.