Snow day calculator

Enter your ZIP code above. The calculator reads the National Weather Service forecast for your area and gives the chance of a closure and of a late start for the next school morning, with the reasons. After 9 a.m. it answers for the next school day; on a Friday evening that is Monday.

It is a real calculation on the real forecast, and it is an estimate. It reads the National Weather Service forecast for your ZIP code and applies published rules to it. It does not know what your superintendent will decide, and no calculator does. The only thing that counts is your district's own announcement.

Anywhere from about 1 inch to 9 inches overnight, depending on how used to snow your district is. Those are the amounts at which the calculator puts closing at even odds. Ice, wind and timing move the line.

It depends on where you live. In districts that rarely see snow, about 1 inch overnight is enough to make closing a coin flip, so 2 inches usually closes school. In districts used to snow the line is nearer 6 inches, and 2 inches means school as usual. Timing matters as much: 2 inches at 6 a.m. does more than 2 inches the evening before.

Yes. A school district can close for the day, start late or send students home early when roads are unsafe for buses, teen drivers and walkers. The superintendent usually decides before dawn. Each district sets its own rules, so neighboring towns can make different calls in the same storm.

This one takes the hour-by-hour forecast for your ZIP code and scores six things: snowfall, when it falls relative to the morning commute, ice, wind chill at bus-stop time, wind and active winter alerts. The score is set against how much snow your area normally handles and turned into a percentage. Every threshold is listed on the How it works page.

It is an estimate. It is only as good as the forecast it reads, and it has had one check against real closings: on 2,024 school days in 17 US districts over two winters, when it said 80% or more schools closed 86% of the time, and it gave under 20% to about three closures in ten. It is most useful the evening before and early on the morning itself, when the forecast is firmest. Your district's own announcement is the only thing that counts.

There is no national rule. The calculator treats a morning wind chill of about -25°F as enough on its own to make a closure a coin flip in districts used to winter, and about -5°F in districts that are not. Cold that severe more often brings a late start than a full closure.

Yes. Ice closes schools at far smaller amounts than snow: about 0.1 inch of freezing rain can be enough. Extreme wind chill, flooding and power outages close schools too. The calculator counts ice and cold; it does not know about floods or outages.

There is none. Pajamas worn inside out, a spoon under the pillow and ice cubes flushed down the toilet are well-loved traditions with no effect on the forecast. What works is snow that falls between midnight and 8 a.m.

Traditionally yes: buildings are closed and there are no classes. Some districts now hold remote learning days instead, so check how your district handles it. Days lost to snow may be made up later in the year.

A delay starts the school day late, usually by two hours, when roads are expected to improve during the morning. A closure cancels the whole day. The calculator gives a separate chance for each.

It skips them. If the next morning is a Saturday, a Sunday, a federal holiday that schools observe or part of winter break, it answers for the next school day and tells you which days it skipped. It does not know your district's own days off.

In Canada, yes: the Canadian calculator takes a postal code and reads in centimetres and °C. Elsewhere, no. US ZIP codes use the National Weather Service, which covers the 50 states, Puerto Rico and Guam.