Snow Day
Guide
How school boards decide to cancel buses or close schools
Most boards and bus consortia in Canada and the northern US make the call between 4:30 and 6 AM, based on what route supervisors see on the roads, whether precipitation is still falling, freezing rain, visibility, the forecast for the rest of the day, and any cold-weather policy. Understanding that process is the key to reading any snow day prediction.
The 5:30 AM call
Long before parents are awake, transportation staff are driving rural routes. They report whether roads are plowed and drivable and whether visibility is acceptable on open stretches. The consortium's manager, often in a call with several boards, decides by about 6 AM so the announcement can go out before drivers start. Most boards publish by 6:30.
What weighs most
- Is it still falling, and how hard? Snow at two centimetres an hour during loading is the single strongest signal.
- Freezing rain anywhere in 4 to 9 AM. Ice on rural roads is close to an automatic cancellation in most of southern Ontario and the Northeast.
- The rest of the day. A storm arriving at 10 AM means buses can't run the afternoon routes.
- Visibility. Blowing snow on open roads, common in Bruce, Grey and Huron counties, eastern Ontario, the Prairies and the Dakotas.
- Cold policy. Winnipeg divisions cancel at a wind chill of −45; several Saskatchewan, Alberta and northwestern Ontario boards at −40 or −45.
- Plow status. Mostly a function of when the snow ended.
Buses versus schools
In Ontario and much of Canada, the common outcome is "buses cancelled, schools open": the building runs with skeleton attendance and parents may drive. Full closures are rarer and usually reserved for freezing rain or a storm forecast to worsen through the day. In many US districts the two decisions are one, plus delayed openings as a middle ground.
Why cancellation culture is local
Rural consortia with long routes and gravel roads cancel a dozen times a winter. Toronto has closed schools a handful of times in twenty years. Southern US districts cancel on a forecast of a few centimetres because they have no plow fleet. The same storm gets a different answer fifty kilometres apart, which is why Snow Day lets you tell it how easily your board cancels.
What this means for predictions
A good predictor should weigh timing over totals, treat freezing rain as its own hazard, know about flash freezes and blowing snow, respect a cold policy where one exists, and let you calibrate for your board. That is exactly how Snow Day is built.