Snow Day Calculator

The calculator takes a base probability from your forecast snowfall, then adds points for cold air, low wind chill, southern region, an overnight start, and private-school status, and subtracts points for a northern region. The base curve is linear: 0 inches maps to 0%, 6 inches maps to 70%, and anything above 6 inches stays capped at 70% on the base alone. The other factors layer on top, with the total capped at 99% so the tool never claims certainty about a chaotic decision.

It is a consumer-grade heuristic, not an official forecast. No school district publishes a closure model. Real decisions depend on local road crews, bus contractor schedules, building heating reliability, and superintendent judgment. The point scoring is calibrated from public reporting on cancellation patterns, so the trends (more snow, colder, southern, overnight equals more likely) are correct. Check your district's website, app, or local news before banking on a day off.

Southern US districts own far less plowing and salting equipment per lane-mile than northern ones. A 2-inch storm that a Minnesota district handles before dawn often closes schools across Tennessee, the Carolinas, and northern Texas because the buses cannot run the routes safely. Northern districts also pre-treat roads and run cold-weather drills as standard practice, which is why this calculator subtracts 10 points for a northern region.

Superintendents in the US typically make the closure call between 4 AM and 5 AM the morning of school. A storm that starts at 10 PM gives accumulation a 6-hour head start over one that begins at 6 AM, so the roads, parking lots, and bus stops are already in bad shape when the decision is on the table. The calculator adds 5 points for an overnight start to reflect that.

Confidence labels how much the inputs lean toward a snow day: below 25% is low, 25 to 50% is medium, 50 to 75% is high, above 75% is very high. The recommended action is a separate threshold: below 40% says plan to attend, 40 to 75% says check the district website tonight, and 75% or above says expect a snow day and prepare for childcare and remote learning. The two scales sometimes disagree in the middle band, which is exactly when checking the official channels matters most.