How the snow day estimate works
- Forecast: your ZIP code is matched to a point on the map, and the National Weather Service forecast for that spot is split into overnight, morning commute, and school-day snow, plus ice, wind chill, and gusts.
- Effective snow: snow before 9 am counts in full, daytime snow counts half, and ice counts heavily because a little ice makes roads dangerous.
- Your area: the same snowfall means more where snow is rare. The calculator compares the effective snow to a typical closing amount for your kind of area.
- Adjustments: extreme cold, blowing snow, the type of school, and snow days already used nudge the result up or down.
See every rule and weight on the how it works page.
Snow day odds at a glance
Estimated chance of a closure with overnight snow only, no ice, and ordinary cold, for a public school that hasn't used any snow days:
| Overnight snow | Rarely gets snow | Gets some snow | Snowy every winter |
|---|---|---|---|
| 1 in | 21% | 5% | 3% |
| 2 in | 79% | 15% | 6% |
| 3 in | 98% | 36% | 12% |
| 4 in | 99% | 64% | 21% |
| 6 in | 99% | 95% | 50% |
| 8 in | 99% | 99% | 79% |
| 12 in | 99% | 99% | 98% |
Snow day FAQ
Is the snow day calculator real?
The forecast is real: it comes straight from the National Weather Service for your ZIP code. The percentage is an estimate made with simple, published rules about snow, ice, cold, and wind. It's meant to be fun and give a sense of the odds, not to predict what your school will actually decide.
Is 2 inches of snow enough for a snow day?
It depends on where you live. With 2 inches overnight and nothing else, our estimate is about 79% where snow is rare, 15% in areas that get some snow, and 6% in snowy regions, which plow 2 inches routinely. Ice makes a much bigger difference than the same amount of snow.
What time is the forecast for?
The calculator looks at snow from 6 pm the evening before through 3 pm on the school day, split into overnight, the morning commute, and the school day itself, plus the lowest wind chill and strongest gust before 9 am. Those are the hours that matter most for buses and roads.
What's the trick for getting a snow day?
Students swear by wearing pajamas inside out, flushing ice cubes, or sleeping with a spoon under the pillow. They're fun traditions with no effect on the weather. The real deciders are how much snow and ice fall before the buses run.
Does it work outside the US?
Automatic forecasts only work for US locations, because they come from the National Weather Service. Anyone can type forecast numbers in by hand and get an estimate.