The project exists for the hours when a storm is approaching and families need to know whether a backup plan is sensible—not for replacing official school communication.
What Snow Day Calculator is
It is a free, account-free web tool that turns a live winter forecast into a school-closure probability, and a set of pages explaining how that number was reached. There is nothing to install, no sign-up, and no paywall. The main calculator combines live forecast variables with six published factors and two broad local settings, then shows every input alongside the result so the reasoning is visible rather than implied.
Around that tool sits a location layer: 30 city pages across 12 states and provinces, regional hubs for each of those, a Canadian country page, and a prediction map that scores every published city at once. Those pages exist because the same percentage means different things in different places, and saying so is more useful than pretending one national number fits everyone.
Why it was created
Most snow day predictors produce a number and stop. That is the opposite of what a parent actually needs at nine o'clock the night before a storm, which is a sense of whether tomorrow is worth planning around and some idea of what could change by morning. A percentage with no visible reasoning cannot answer that, and a percentage presented as a verdict is worse than useless because it invites people to stop checking.
So the design goal here was the opposite: publish the model, show the forecast values, separate official weather alerts from the site's own scoring, name what the model cannot see, and send readers back to their school district for the decision itself.
Who maintains it
One developer, working alone, who writes the code, the scoring model and every page on the site. There is no editorial team and no meteorologist on staff, and the site does not claim either. The full account of who does the work, what is built, how the data flows and what is deliberately not claimed is on the who maintains this page.
Which weather factors are considered
Forecast snowfall and possible icing, minimum and maximum temperature, calculated wind chill, maximum wind, total precipitation and precipitation probability, plus the hour-by-hour distribution of snow across the previous evening, the overnight period, the 5–9 a.m. transportation window and normal school hours. Two user-selected settings supply broad local context: area type and school level, with a district-tendency control that nudges an existing non-zero estimate. Every threshold is published on the methodology page.
Which data sources are used
- Open-Meteo for geocoding and all forecast variables, through its documented forecast API.
- The National Weather Service API for active U.S. winter alerts, shown beside a result as official context and deliberately excluded from the score.
- Environment and Climate Change Canada for Canadian warnings, linked rather than embedded because the automated check does not cover Canada.
- Hand-written local context on every location page, containing no snowfall averages, closure counts or district thresholds.
Limitations, stated plainly
The calculator cannot see road treatment progress, plow routing, staff and driver availability, building power or heating, an individual hill or bridge, a consortium's zone map, or the judgement of the person making the call at five in the morning. It publishes no accuracy percentage, because verifying one would require a complete history of forecasts and decisions for every district covered. It invents no closure threshold for any named school system.
Final closure decisions are made by schools, districts, boards, divisions and service centres — never by this site. A school system can close buildings, delay the start, cancel transportation only, dismiss early or switch to remote instruction, and those outcomes are not interchangeable. The accuracy and limitations page covers this in full.
Editorial standards
- Separate a forecast estimate from an official school announcement, on every page.
- Publish no accuracy percentage and no “most accurate” claim.
- Invent no weather statistic, closure count or district threshold.
- Name the data source for every number shown.
- Claim no credential that is not held.
- Use descriptive image alternatives and original visuals.
- Link related guidance contextually, not only in recommendation blocks.
- Publish no reviews or ratings, and accept no paid placement in rankings.
When the methodology was last reviewed
The scoring model and its published description were last checked against the source code on . Automated checks run before every deployment and fail the build on a duplicate title or description, a missing or duplicated canonical URL, a page without exactly one H1, a broken internal link, invalid structured data, a canonical URL missing from the sitemap, or near-duplicate location prose. Location pages carry their own review dates, and guides show when they were last updated.
How to report a problem
If you find a calculation bug, broken link, accessibility issue or factual error, use the contact page. Include the page URL and enough detail to reproduce the issue, but do not send sensitive student or school records.
Before using any result, review the accuracy and limitations statement and confirm the final status with your school district.