References & Sources

The primary US federal agency for weather science. NOAA's National Weather Service provides official forecasts, watches, warnings, and historical climate data used to understand regional snowfall patterns.

Provides official US weather forecasts, winter storm warnings, wind chill advisories, and snowfall accumulation estimates. A key reference for understanding how forecasters classify winter weather severity.

The free, open-source weather API that powers Snow Day Calculation's live predictions. Aggregates data from multiple numerical weather prediction models including GFS, ECMWF, and others.

One of the world's leading numerical weather prediction centers. The ECMWF model (IFS) is widely regarded as among the most accurate global forecast models, especially for medium-range predictions.

The Canadian federal weather authority. Provides official forecasts, winter weather warnings, and climate data used to calibrate regional closure thresholds for Canadian locations.

Federal guidance on school operations, emergency closures, and the impact of unplanned school days on academic calendars. Referenced for context on how districts handle emergency closures.

Individual US state education departments set policies on minimum instructional days and how snow days can be made up. These policies vary by state and influence how aggressively districts call closures.

Canadian federal and provincial education resources, referenced for understanding school calendar and closure policies across Canadian provinces.

Educational resource from the National Weather Service explaining winter storm classifications, wind chill charts, and safety thresholds — used as a reference for understanding when conditions typically prompt closure decisions.

A leading research center for snow, ice, and cryosphere data. Provides historical snowfall records and climate datasets referenced for understanding regional snowfall norms.

The world's largest archive of atmospheric, coastal, geophysical, and oceanic data. Referenced for historical snowfall records and climate normals used to calibrate regional probability weights.

Technical reference for the weather API that powers Snow Day Calculation. Describes available variables, forecast models, update schedules, and data accuracy characteristics.

Used to convert typed city names and postal codes into geographic coordinates for weather lookups.

The open-source charting library used to render historical snowfall trend charts in the calculator.