How school boards decide snow days

There is no national snow-day rule, and there is no switch in Ottawa that closes every school at once. The decision sits with the authority that runs the school: a district school board, a school division, a regional centre for education, a Quebec school service centre, or a provincial body such as NLSchools or Prince Edward Island's Public Schools Branch. Transportation is often a second decision, made by a consortium the boards created to run the buses.

What they can actually see

By the time someone has to choose, the useful information is local and slightly stale. Road supervisors and bus operators report what the yards and the first routes look like. The forecast still matters, especially if the worst of the snow or freezing rain is expected to arrive while buses are already out. Facilities staff care whether parking lots, stairs, and sidewalks can be made safe. A board can also close because the building has no power or no heat, which a snowfall total will not tell you.

Timing is the quiet factor. Snow that falls at supper and then stops gives plows a night shift. Snow that intensifies at 5 a.m. lands on top of the decision. Some consortia publish a target window for posting cancellations. Simcoe County's consortium, for example, says it aims for 6:00 to 6:30 a.m. That is one organization's practice, not a Canadian standard. If your consortium does not publish a clock time, do not invent one from a neighbour's board.

Why the same storm looks different across town

Urban walking networks, suburban loops, and long rural routes do not fail at the same moment. A city can keep schools open for students who walk or take public transit while cancelling yellow buses in a rural zone. Halton Student Transportation Services even publishes separate weather zones for that reason. Quebec boards and service centres decide for their own schools, so an English board and a French service centre in the same city can post different notices.

Extreme cold is its own category. Prairie and northern boards sometimes cancel for wind chill on a clear morning. Coastal boards are more likely to be dealing with ice and a quick change from snow to rain. None of that collapses into a single centimetre threshold, which is why our methodology publishes a formula instead of a magic number.

What to do with the estimate

Use a predictor the evening before, when you still have time to arrange work and childcare. Use the board and the transportation site in the morning, when the decision exists. If those two disagree with the score, the official sites win. We do not receive their calls, and we do not store a history of who closed when. A careful account of how accurate a forecast can be is in is a snow day predictor accurate?.