Snow day probabilities

I just learned that Snow Day Calculator exists, and will tell you the probability of having a snow day from school tomorrow.
Here’s an interview with David Sukhin, its creator, currently a junior at MIT. It appears AccuWeather has a similar predictor. See also the reddit snow closing map.

I’d be interested to know how accurate these forecasts are. The big difficulty here seems to be, as with so many prediction problems, gathering the data set. There are good records of actual snow amounts – but school closures (the dependent variable) and historical weather forecasts (the independent variable, if we want to avoid leakage from the future) are going to be much harder to find. (An easy way to deal with this, once you have a critical mass of users – let them submit whether their school closed today or not?) There has been analysis of the effect of snow days on educational outcomes, but the only thing I could dig up on predicting the probability of snow days is this paper on defining a severity index for snow storms from the National Weather Digest in 1985, which lucked into having a high school with good records. That won’t scale.