Going to bed on the night of a snowstorm and wishing for a snow day is a rite of passage as a kid. But not all flakes are created equal — and where you live can play a big role in whether that wish comes true.
How much snow causes school closures varies dramatically across the US. In some places, especially in southern states, it can take less than two inches, like in Tulsa County, Oklahoma. But in more wintry parts of the country like New York, some parts of the state can handle more than a 10-inch snow dump before schools shutter.
View this interactive content on CNN.comOn the shores of Lake Erie, Buffalo is a regular target of big lake-effect snow events often measured in feet, not inches. In Erie County, where the city resides, residents will have to wait for the snow to accumulate to about 8.8 inches on average before districts make the decision to shut schools for the day.
Over 9 inches of snow separate the most and least snow-resilient counties, according to a data analysis by Snow Day Calculator, a website and app that lets users predict the likelihood of school closures in their area. The calculator works by combining weather data from the National Weather Service, along with other factors, like zip code, school type and previous closures, to calculate the probability school will be canceled.
David Sukhin, who created the calculator, said he has observed that factors like local terrain – if an area is flat or hilly – and a place’s level of winter preparedness – readily available salt trucks and snow plows – can affect how likely a school district is to close due to snow.
“Different areas in the US are used to very different amounts of snow,” said Sukhin. “Some areas in the Northeast are ready to deal with 5-plus inches on a regular basis, while areas farther south close down for just a few inches.”
View this interactive content on CNN.comThe type of school can play a role too. In many states, public schools are mandated to hold a minimum number of instructional days, and if school cancellations pile up, snow days are harder to call. On the other hand, private schools don’t have the same requirement, so they can cancel school with more flexibility. Rural school districts also up the odds. If students are bussed in from far distances, poor driving conditions are likely to cancel school. The Snow Day Calculator takes into account whether a school is private or public when making its predictions.
In general, around 5 to 6 inches of snow is the national sweet spot.
View this interactive content on CNN.comUltimately predicting snow days is about a lot more than weather, said Sukhin. Snow clean up logistics aside, sometimes it boils down to the leniency of the school administrator calling the shots and a little bit of luck.
Use our interactive map to search for the snow day average in your county.
View this interactive content on CNN.com