Snow Day Calculator – Will School Be Closed?

Disclaimer: This tool estimates the probability of a snow day based on forecast weather conditions and the factors used by our prediction model. Your local school district makes the final decision, and conditions can change overnight.

Snow Day Calculator is a free tool that estimates the chance of school closing tomorrow due to winter weather. Enter your US ZIP code, Canadian postal code, or city name into the predictor above to see your snow day probability for the next 24 hours, plus a 5-day forecast and recent snow day history for your area.

Whether you call it a snow day calculator, a snow day predictor, or a school closure forecast, the goal is the same: knowing in advance whether tomorrow’s storm is likely to cancel school. Instead of guessing or refreshing the news at midnight, this tool gives you a clear percentage based on real weather data.

How to Use the Snow Day Calculator

The calculator is designed to be simple. Three steps:

1. Enter your location: Type a US ZIP code (like 10001 for New York), a Canadian postal code (like M5V 2T6 for Toronto), or a city name (like Boston or Calgary).
2. Choose your district policy: If your school district closes easily at the first sign of snow, pick “Liberal.” If your district almost never closes, pick “Conservative.” Most districts are “Neutral.”
3. Click Get Snow Day Prediction: The calculator pulls live weather data and shows your snow day chance as a percentage, plus details on tomorrow’s expected snowfall, wind chill, and any weather alerts.

If you want to test different conditions yourself, for example, “what if 6 inches of snow falls during the morning commute?” switch to the Manual Calculator tab and adjust the sliders.

How the Snow Day Predictor Works

School closure decisions are not based on snowfall alone. Districts weigh several factors at once. The calculator combines seven real weather variables to estimate the chance of closure:

• Snow accumulation: Total inches expected over the next 24 hours
• Wind chill: How cold it will feel at bus stops, calculated using the standard NOAA wind chill formula
• Ice and freezing rain: Often more dangerous than snow, since untreated ice closes schools even at small accumulations
• Morning timing: Storms hitting between 5:00 AM and 9:00 AM (the “bus window”) are more likely to trigger closures than overnight storms that finish before dawn
• Wind speed: High winds combined with snow create blizzard conditions and reduce visibility for buses
• Visibility: Heavy snow that limits visibility below safe driving distances raises closure risk
• District policy: Some districts close at the first inch; others stay open through major storms

The calculator retrieves hourly forecast data through Open-Meteo, which combines weather-model output from providers including NOAA in the United States and Environment and Climate Change Canada. Our calculator then applies its own weighting to the seven factors above and combines them into a single snow-day probability estimate. The percentage is an estimate based on forecast conditions, not an official school closure prediction.

Learn more about what conditions increase school closures.

Snow-Calculator.com was built by Tayyab Ali. Learn more about the calculator, its methodology, and its limitations on our About Us page.

What Your Snow Day Chance Percentage Means

The result is shown as a percentage from 0% to 100%. Here’s how to read it:

• 80% or higher – Very high estimated chance. Forecast conditions strongly favor possible school disruption.
• 55% to 79% – High estimated chance. A closure or delay is a meaningful possibility.
• 30% to 54% – Moderate or borderline chance. Small forecast changes could significantly affect the result.
• 10% to 29% – Low estimated chance. Current conditions do not strongly favor a closure.
• Below 10% – Very low estimated chance. Few closure-related weather factors are currently present.

A higher percentage means the calculator sees a stronger combination of weather conditions associated with possible school disruption. The percentage is not a measured historical closure frequency or a guarantee.

Snow Day Calculator for the United States

The calculator works across all 50 US states using ZIP code lookup. It’s especially useful for areas where snow days are common, including the Northeast (Boston, New York, Buffalo), the Midwest (Chicago, Minneapolis, Detroit), the Mid-Atlantic (Philadelphia, Washington DC), and northern states like Maine, Vermont, and North Dakota.

Winter weather can have very different impacts across the United States. Areas with extensive snow-removal equipment may continue operating during conditions that would cause major disruption somewhere less accustomed to winter weather. This is why the calculator includes a school district policy setting, allowing users to better reflect how readily their local district typically responds to snow and ice.

Snow Day Predictor for Canada

The snow day predictor also supports Canadian postal codes and city names. Winter-weather policies vary between Canadian school boards just as they do between U.S. school districts, so snowfall alone should not be treated as an automatic closure threshold. Enter your postal code or city and select the district-policy setting that best reflects your local school board.

Snow Day vs. Delayed Start vs. Early Dismissal

Not every winter storm leads to a full school closure. Districts have several response options depending on storm timing and severity:

• Full snow day (school closed): Used when conditions are unsafe throughout the entire school day, or when the morning is dangerous and unlikely to improve quickly.
• Delayed start (1- or 2-hour delay): Used when the worst conditions are expected to clear before mid-morning. This gives crews time to plow roads and treat ice before buses run.
• Early dismissal: Used when a storm is forecast to arrive during the school day, allowing students to get home before conditions deteriorate.
• Remote learning day: Increasingly common since 2020, where school continues online instead of canceling entirely.

The calculator estimates the probability of closure or delay as a single percentage. A 60% result, for example, often indicates a meaningful chance of either a full closure or a delayed start.

How Much Snow Is Needed for a Snow Day?

There is no single snowfall amount that guarantees a snow day. The effect of snow depends on where and when it falls, whether ice is involved, road and bus-route conditions, visibility, local snow-removal capability, and school district policy.

For example, a smaller snowfall combined with freezing rain during the morning commute may cause more disruption than a larger snowfall that ends several hours before buses begin running. Areas accustomed to frequent winter storms may also handle snow differently from places where significant snowfall is unusual.

For a detailed explanation, read What Conditions Increase the Chances of a School Closing?.

How Accurate Is the Snow Day Calculator?

The calculator provides a probability, not a guarantee. Accuracy depends on three things:

1. Weather forecast accuracy. Short-range forecasts generally have less uncertainty than forecasts made several days in advance, but winter conditions can still change significantly as a storm approaches.
2. How well your district matches the “Neutral” default. If your specific district is unusually cautious or unusually strict, selecting the setting that best represents your district can make the estimate better reflect its typical behavior.
3. Local conditions the forecast can’t fully capture. Things like a single icy bridge, a power outage at the school, or a sudden temperature shift can affect closure decisions in ways the forecast doesn’t predict.

For a deeper look at prediction accuracy and how forecasts compare to actual school closures, read our analysis of how accurate snow day calculators really are.

Why the Calculator Is Better Than a Regular Weather App

A weather app tells you how much snow is forecast. The calculator translates that data into the question you actually care about: will school be closed tomorrow?

Snow accumulation alone is a poor predictor of school closures because it ignores timing, ice, wind chill, and district behavior. A 70% snow day chance in a northern Vermont town and a 70% chance in suburban Atlanta both mean the same thing, closure is likely, even though the underlying weather is completely different. That’s the value of a probability-based tool over a raw weather forecast.

Frequently Asked Questions