Snow Day Predictor

Snow Day Predictor is a planning tool that turns weather inputs into a transparent snow-day prediction. It is designed for practical decisions such as school planning, travel timing, and winter-weather preparation.

The predictor uses the same Snow Day Model as the calculator but presents the result as a broader planning estimate with extra emphasis on confidence and source transparency.

Choose manual mode when you already have a forecast or want to test assumptions. Choose live mode to search a location, pull an Open-Meteo hourly forecast, and include US alert context when NWS alert data is available.

• Enter or fetch the weather inputs.
• Review the factor scores and confidence label.
• Use the result as planning context, not as an official decision.

Live mode uses Open-Meteo forecast data for hourly weather variables. For US locations, NexaCalc also attempts to read active National Weather Service alerts on the server.

If live data is unavailable, manual mode remains fully deterministic. Manual inputs are useful for comparing forecast scenarios or entering data from a trusted local source.

Snow Day Model v1.0.0 combines weather factors on a 0 to 100 scale. Each visible factor shows its input, score, weight, and contribution so the final output is not a hidden black box.

When a factor is unavailable, the remaining available weights are re-normalized and the confidence label is reduced. The final score is clamped between 0 and 100.

Snowfall, ice, timing, road ice, temperature, wind, visibility, and alerts describe different parts of the same event. A light snow during a quiet afternoon is different from the same snow during a morning commute with poor visibility.

• Snowfall estimates accumulation impact.
• Ice and road ice estimate freezing precipitation and slick-surface risk.
• Timing captures whether the hazard overlaps school opening or travel.
• Alerts add source-labeled warning context when available.

Confidence is separate from the risk or chance score. A high score with low confidence means the available inputs look hazardous, but important data was missing.

Live forecasts can be partial if alerts are unavailable or if a provider omits a field. Manual calculations show high confidence only when all required user inputs are present.

For example, a forecast with significant snow, some ice, morning overlap, cold road surfaces, wind, low visibility, and a winter warning will produce a higher snow-day prediction than the same snow amount after school has already opened.

The factor table below the result is the best way to inspect why the score moved up or down.

The result card shows whether the result came from manual inputs, live data, partial live data, or cached provider data. NexaCalc does not claim ownership of live weather data.

Open-Meteo and NWS labels are shown as data sources when those providers are used.

Weather conditions can change quickly, and local decisions may depend on staffing, road treatment, bus routes, district policy, power outages, building conditions, and official emergency guidance.

NexaCalc does not guarantee snow days, school closures, safe travel, or outdoor safety. Always follow local authorities and your school, workplace, or road agency.

Manual calculations run in the browser. Live mode sends the searched location or coordinates to the NexaCalc server so it can request weather data. Shared result text avoids including precise coordinates.

Weather tools provide planning estimates only. They are not official forecasts, emergency guidance, school district decisions, or travel-safety instructions.

For severe weather, road closures, emergency warnings, frostbite risk, or school decisions, use official sources and local instructions.

This page uses Snow Day Model v1.0.0. NexaCalc lists the model version so future formula changes can be reviewed and tested without silently changing the method.

• Open-Meteo Forecast API documentation for hourly forecast variables and forecast access. Source.
• Open-Meteo Geocoding API documentation for location search and coordinates. Source.
• National Weather Service API documentation for public alerts and required User-Agent usage. Source.
• National Weather Service winter weather safety guidance for general winter hazard context. Source.

Weather reference families reviewed against Open-Meteo and National Weather Service documentation on June 21, 2026.