About Us

Snow Calculator is a free tool that estimates the chance of school being closed tomorrow because of winter weather. You enter a US ZIP code, a Canadian postal code, or a city name, and it returns a percentage based on tomorrow’s forecast.

That’s the whole product. This page explains who built it, why, and how it works.

Who built this

I’m Tayyab Ali, a web developer based in Pakistan. I built and run snow-calculator.com on my own. There’s no team, no investors, no parent company, just me and the tool.

You can find me on LinkedIn, and the email below goes directly to my inbox.

Why I built it

In early 2025 I was looking at the existing snow day calculators online and noticed two things. First, most of them were old, built years ago, running on simple “X inches of snow = Y% chance” logic that ignored almost everything that actually matters: ice, wind chill, the timing of the storm, the specific habits of the local school district. Second, none of them clearly explained where their numbers came from.

I’m a developer, not a meteorologist. But I knew that “how likely is school to close tomorrow” is a calculation problem, not a forecasting problem and that the inputs are public. The forecasts already exist. The school closure patterns already exist. What was missing was a tool that combined them transparently.

I launched snow-calculator.com in early 2025 and have been refining the model through the 2025–2026 winter season.

How the calculator works

The calculator pulls hourly forecast data from Open-Meteo, a free weather API that aggregates forecasts from national meteorological services, including the National Weather Service (NWS) in the United States and Environment Canada. Open-Meteo is the data source; NWS and Environment Canada are the original forecasts feeding into it.

For each location you enter, the tool reads the next 24 hours of forecast data and runs a weighted scoring model across seven factors:

  1. Snow accumulation – total inches expected
  2. Ice and freezing rain – weighted heavily because ice closes schools at much lower amounts than snow
  3. Wind chill – calculated using the standard NOAA formula
  4. Storm timing – storms hitting between 5–9 AM (the bus window) score higher than overnight storms that finish before dawn
  5. Wind speed – high winds combined with snow create blizzard conditions and reduce visibility
  6. Visibility – heavy snow that drops visibility below safe driving distance raises closure probability
  7. District policy – the optional Liberal / Neutral / Conservative selector adjusts the threshold based on how easily your specific district closes

Each factor has a weight. The weighted scores are combined into a single probability percentage between 0 and 100. The full formula and weight values are documented on the homepage.

What this tool is not

It’s worth being clear about the limits.

This is not an official source. Your school district makes the closure decision based on real conditions on the morning of the storm, including things no public forecast captures, like a specific icy bridge on a bus route, a power outage at the school building, or a last-minute change in storm track. The calculator estimates probability. It does not predict the decision.

It’s not always right. Forecasts are most accurate 12–24 hours out. Beyond that, uncertainty grows. In borderline weather, a few inches that could either close schools or not, even meteorologists disagree, and the calculator inherits that uncertainty. The percentage is a forecast of a forecast, and you should treat it as one.

It doesn’t replace official channels. When schools actually close, you’ll find out from your district’s website, email list, app, or local news. The calculator is for the night before, when you want a realistic read on the odds before going to sleep.

If you find a case where the calculator’s prediction was off in a way that seems systematic, an entire region it consistently mis-estimates, for example, I’d genuinely like to hear about it. Email below.

Contact

LinkedIn: Tayyab Ali
Email: tayyab.ali@snow-calculator.com

I read everything that comes in. Feedback on the model is especially welcome.