Will there be a snow day tomorrow?

Every 15 minutes HQ decodes the latest Environment Canada city forecast for each place: snow amounts for the night and morning, the hourly conditions during the bus run, wind and blowing snow, morning wind chill, and any warnings in effect. Each clue becomes a chance, scaled for how easily buses stop in that kind of place (a rural route on hills cancels with way less snow than a big-city board), and the clues combine into one number.

No. Only your school board or its bus consortium makes the call. The predictor is our best estimate from the forecast. On the morning itself, the live bus status on our region pages comes straight from the official transportation sites.

Transportation consortia usually decide early in the morning, before the first buses leave, and post it on their own website and social accounts. That is often between about 5:30 and 7:00 a.m. Check your region page for the live status.

In most of Ontario, a bad-weather morning cancels the buses but schools stay open for students who can get there safely. A full closure, where schools are closed to students, is rarer. The predictor gives the chance of either: buses cancelled or schools closed.

Ploughs clear snow, but ice on rural roads and hills makes it unsafe to stop and start a loaded bus. A few millimetres of freezing rain during the morning run cancels buses in many regions that would run through 10 cm of snow.

It is only as good as the forecast, and forecasts the night before can change while you sleep. Check again first thing in the morning. HQ logs every prediction and every official decision, and uses that history to sharpen the model for each region.