Will tomorrow be a snow day?

Enter your ZIP code, postal code, or city and your brief shows tomorrow's chance of closure, next to the chance of a delayed start, a remote day, and a normal school day. It's a probability, not a yes or no, because the forecast is one too.

The number can move through the evening as new forecasts arrive, so every brief shows when it was last updated. If it's still moving late at night, the storm's timing or track hasn't settled yet, and neither has the morning.

It scores four signals and turns them into a chance for each of four outcomes: open, delayed start, closed, and remote day. The signals are the forecast, temperature and ice, official alerts from the National Weather Service or Environment and Climate Change Canada, and how much snow your area is normally used to.

Timing matters as much as totals. Eight inches that stop falling at midnight and get plowed by five is a normal school day. Three inches starting at 5 AM, inside the decision window, is the one that closes schools. Your brief lists every factor that moved your number, biggest first. The long version is on the method page.

We don't have a season of results yet, so we're not going to put a number on it. This is Snow Brief's first winter, and accuracy can't be measured until enough school days have gone by.

What we do instead is keep receipts. Every prediction is saved the moment it's published, and we don't edit it afterward. The 8 PM and 4 AM calls also keep the forecast they were made from. On mornings when school was in doubt, your brief asks whether you got a snow day.

After big storms we'll compare our calls with the closings that were announced and publish the results, misses included.

Usually low, even in a snowy week. On most winter mornings school opens on time, so a number under 20% is the normal reading, not a broken one. Your brief gives the figure for your area.

Read the number as what it says. A 30% chance of closure means schools open on most mornings that look like this one, and close on some of them. The line under the percentage puts it in words: unlikely, possible, leaning likely, or likely.

Yes. Snow Brief covers both countries, and each brief follows the country your location is in. Canadian locations get centimeters, degrees Celsius, and school board language; US locations get inches, Fahrenheit, and school districts.

The forecast source changes too. Canadian briefs run on Environment and Climate Change Canada data, US briefs on the National Weather Service and NOAA. There's one catch. The Canadian feed publishes snowfall per forecast period, not hour by hour, so timing north of the border is less precise. The brief says so where it matters.

Between 7 and 10 PM. By then the evening forecasts have landed, and you still have time to arrange childcare or set an alarm differently.

Then check again in the morning. The call is usually made between 4 and 7 AM, after someone has driven the bus routes, so a brief that looked settled at 9 PM can still change on ice that arrived at 5. If you'd rather not keep checking, turn on alerts. When there's a 30% or better chance school won't open as normal, we send your brief at 9 PM, and a correction before 5:30 AM if the number moves.