How Snow Day Alerts Works

What Snow Day Alerts is designed to do

Snow Day Alerts estimates the likelihood of a school closure based on weather conditions that historically create difficult or unsafe travel during school mornings. The system is designed around one key reality: most closure decisions are made in a narrow early-morning window, usually between 4 and 5 AM.

Instead of looking only at daily snowfall totals, Snow Day Alerts focuses on timing, accumulation, and impact — the factors that matter most when districts decide whether buses can run safely.

Weather data inputs

For each ZIP code, the system analyzes short-range weather forecasts using:

• Overnight snowfall accumulation
• Snowfall and precipitation during the early-morning commute window
• Freezing rain or refreeze risk
• Wind speed and gusts that can cause drifting or blowing snow
• Minimum temperatures and wind chill for students waiting outdoors

Why timing matters more than totals

A storm that drops several inches during the afternoon may have little impact on schools the next day if roads are cleared overnight. On the other hand, even a modest amount of snow or ice that falls between midnight and sunrise can create dangerous conditions.

Snow Day Alerts places extra weight on weather conditions occurring from 6 PM through noon the following day, with the highest emphasis on the overnight and early-morning hours.

Regional adjustments

Snow readiness varies widely across the United States. Northern regions often remain open during moderate snowfall, while areas that see snow less frequently may close with much smaller amounts.

To reflect this reality, the scoring system adjusts expectations based on regional snow climatology rather than applying a single nationwide threshold.

Scoring and interpretation

All weather factors are combined into a score from 0 to 100. The score is then translated into descriptive categories designed to be informative without overstating certainty:

• No Snow Day Signal (0–19%) – Typical winter conditions.
• Low Snow Day Signal (20–39%) – Something to monitor.
• Snow Day Possible (40–59%) – Conditions worth watching closely.
• High Snow Day Signal (60–79%) – Setup resembles past closure events.
• Very High Snow Day Signal (80–100%) – Strong alignment with closure patterns.

Important limitations

Snow Day Alerts does not use official school district data and does not predict individual district decisions. Local factors such as staffing, bus routes, road treatment priorities, and district policies can override weather conditions.

The odds are intended as a planning tool — not a guarantee. Always rely on your school district’s official communications for final decisions.