Free Online Tool

Snow Day Calculator

Predict your chances of a school snow day using real-time NOAA weather data.

Snow Day Calculator

Powered by NOAA · National Weather Service · Open-Meteo

About Snow Day Calculator

The ToolSquirrel Snow Day Calculator uses real-time data from the National Weather Service (NWS) and Open-Meteo — the same models used by NOAA — to predict the probability of school closures for any US ZIP code. Our weighted algorithm evaluates snowfall accumulation and timing, active NWS winter storm warnings, ice and freezing rain probability, wind chill, and regional school closure thresholds to give you an accurate, honest prediction. Unlike other snow day calculators, we show you exactly why we made our prediction and update automatically as forecasts change. Completely free, no sign-up required.

How to Use Snow Day Calculator

  1. 1

    Enter Your ZIP Code

    Type your 5-digit US ZIP code into the search box. The calculator works for all 50 states.

  2. 2

    Select School Type

    Choose between Elementary/Middle School, High School, University, or Workplace to get a prediction calibrated to your institution's typical closure threshold.

  3. 3

    View Your Snow Day Probability

    Instantly see your snow day probability score (0–100%) along with a plain-English verdict and the top factors driving the prediction.

  4. 4

    Check the 5-Day Forecast

    Scroll down to see snow day probability for the next 5 days so you can plan ahead for the whole week.

  5. 5

    Share Your Result

    Use the share button to send your snow day prediction to classmates, family, or social media.

Pro tip: Bookmark this page (Ctrl+D / Cmd+D) to easily access this tool whenever you need it.
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Why Choose Our Snow Day Calculator?

Secure Processing

All processing is done securely. Your files are automatically deleted after 5 minutes.

High Quality Output

Advanced algorithms ensure the best possible output quality for your files.

Completely Free

No hidden fees, no credit card required. Use our basic tools free forever.

No Installation Needed

Everything runs in your browser. No downloads, plugins, or software required.

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Frequently Asked Questions

How accurate is the Snow Day Calculator?

For next-day predictions (within 24 hours), our calculator achieves 80–90% accuracy for major snow events of 4 or more inches. Accuracy drops to 65–75% for 3–4 day forecasts. Borderline events (1–3 inches) are harder to predict for any tool. We are always transparent about confidence levels.

What data sources does the Snow Day Calculator use?

We use two completely free and authoritative sources: the Open-Meteo API (which is built on NOAA GFS and HRRR models — the same models used by the National Weather Service) and the official NWS Alerts API from weather.gov for active winter storm warnings and advisories.

Why does my region need a different threshold than another?

Schools in the Deep South (Texas, Georgia, Alabama) typically close with just 1–2 inches of snow because they rarely see it and infrastructure isn't prepared. Schools in the Upper Midwest (Minnesota, Wisconsin) may stay open with 8–10 inches. Our calculator accounts for these regional differences.

Why does the Snow Day Calculator matter more than a weather forecast?

A weather forecast tells you how many inches of snow are expected. A snow day calculator tells you what that amount of snow means for your school. Those are very different questions. We factor in precipitation timing (before 6 AM vs. afternoon), ice conditions, wind chill, active NWS warnings, and historical regional closure patterns.

Does this work for all US states?

Yes. The calculator works for any valid US ZIP code across all 50 states. It automatically adjusts predictions based on regional thresholds and historical closure patterns for your area.

Is there a mobile app?

Our web calculator is fully mobile-optimized and works on any smartphone browser. You can add it to your home screen for quick access — no app store needed.