Greater Toronto Area
In Toronto the usual outcome of a bad winter morning is a bus cancellation, not a closed school, and those are two different announcements. The estimate below is loaded with live Toronto forecast data.
Live Toronto forecast estimate
Enter a location to compare tomorrow's snow, ice, temperature, wind and morning timing.
Local conditions
Toronto sits on the north shore of Lake Ontario, which moderates the city's temperature and often puts it right on the boundary between snow and rain. The lake keeps the waterfront milder than inland communities, so a system delivering plowable snow to areas north of the city can arrive downtown as slush. Separately, snow squalls forming over Lake Huron and Georgian Bay occasionally track southeast far enough to reach the northwest edge of the GTA, bringing sudden visibility loss that behaves nothing like a steady snowfall. Toronto is also intensely transit-dependent, which changes what a winter morning actually threatens.
What actually drives a decision
Across the GTA, student transportation is operated by consortia serving multiple boards, and they announce transportation cancellations by geographic zone early in the morning. Schools very often stay open with staff on site while buses do not run. A high weather-pressure estimate here should send you to the consortium's zone status, not to a search for a closure notice.
Lake Ontario's stored warmth can lift shoreline temperatures just enough to change precipitation type. Read the temperature factor and precipitation values rather than snowfall alone, and expect a forecast for the GTA to verify differently downtown than in York or Durham Region.
A large share of Toronto students travel on the TTC or on foot. Sidewalk, crossing and platform conditions before dawn therefore matter as much as road clearing, and staff travelling in from across the region face their own conditions. Those are operational realities the weather model does not observe.
Systems arriving with a warm layer aloft produce ice rather than snow, and a glaze across the GTA's road and sidewalk network is far more disruptive than its lack of depth suggests. Check whether the snow-and-ice factor cites an icing signal.
The forecast for the coordinates above is scored against six weighted factors: snow and ice, temperature, wind chill, morning timing, area and routes, and school level. Around Toronto the rows that most often carry the number are temperature, snow and ice, morning timing. Every factor appears in the result with its own value, score bar and published weight, so a percentage is never presented without the reasoning behind it. The methodology page documents each threshold, and the accuracy and limitations page sets out what the model cannot observe.
This site does not publish closure thresholds for any school system, because those are operational judgements rather than published numbers. What it can do is point you at the organisations that actually decide. Around Toronto, ON those include:
Treat the estimate on this page as a reason to prepare and to keep checking, never as an announcement. A school system can close buildings, delay the start, cancel transportation only, dismiss early or move to a different learning format, and those outcomes are not interchangeable.
Primary sources for weather warnings and road conditions covering Toronto. School decisions still come from the systems listed above.
Toronto questions
Probably not closed, and that is the honest answer for Toronto. Board-wide closures are uncommon here; the realistic outcome is a zone bus cancellation announced by the transportation consortium while schools stay open. Check the consortium status first, then your board's notice.
Most often buses are cancelled while schools remain open. Transportation cancellations are announced by zone by the consortium serving the boards, and a board-wide closure is a separate and less frequent decision.
A transportation cancellation, by a wide margin. Board-wide closures are uncommon in the city, so a high estimate here is best read as a prompt to check the consortium's zone status and to work out how a child would reach a school that is still open.
Tomorrow is the one to act on, and the five day tabs are there for planning further out. Because the lake keeps Toronto close to the rain-snow boundary, a day-four estimate here is less stable than the same estimate would be for a colder inland city.
Still deciding what to do with the number? Read how schools make the final call and the guide to the best times to check a forecast.