Ontario Snow Day Predictor — Will School Be Closed Tomorrow?
Check the chance of a snow day or bus cancellation anywhere in Ontario. Type your city or postal code to get a live score built from current weather and how your local school board has acted in past storms.
Is It a Snow Day Today or Tomorrow in Ontario?
To find out, type your city or postal code into the tool above. You get a live percentage for a snow day or bus cancellation, based on current Ontario weather and how your school board has closed in the past. For the clearest read, check the night before a storm and again early the next morning.
Ontario is huge, and its winters are not the same from one corner to the next. A storm that shuts schools in Sudbury can leave Toronto with clear roads on the same day. That is why a single province-wide number does not tell you much. The tool above gives you a score for your exact spot, and the sections below explain what drives that score in each part of the province.
Snow Day Chances by Ontario City
Winter hits every Ontario city differently. Here is a quick read on the places people check most. Tap any city name to run a live score for it in the tool above.
Toronto & the GTA
2–5 closures/yearStrong road crews and Lake Ontario keep closures low. TDSB, TCDSB, Peel, York, Durham, and Halton serve this area.
Check Toronto →Hamilton
3–6 closures/yearThe Niagara Escarpment and lake-effect bands off Lake Ontario can hit the Mountain harder than downtown.
Check Hamilton →London
3–6 closures/yearLake Huron squalls can drop heavy snow fast. TVDSB and LDCSB often cancel buses before a full closure.
Check London →Ottawa
5–8 closures/yearThe Ottawa Valley storm track brings frequent big snowfalls. Four boards serve the city.
Ottawa forecast →Barrie & Simcoe
6–10 closures/yearGeorgian Bay lake-effect snow can bury Barrie in hours. SCDSB and SMCDSB act fast on squalls.
Check Barrie →Sudbury & the North
8–12 closures/yearThe highest closure rate in Ontario. Heavy snow and long rural bus routes drive it up.
Sudbury guide →Kitchener–Waterloo
3–6 closures/yearWRDSB and WCDSB cover Kitchener, Waterloo, and Cambridge, where bus cancellations are common.
Check Waterloo →Kingston
5–8 closures/yearEastern Ontario storms and lake-effect off Lake Ontario shape Kingston’s winters.
Check Kingston →Windsor
2–5 closures/yearOntario’s southern tip has the mildest winters, so full closures stay rare.
Check Windsor →Do not see your town? The tool works for every Ontario location, including Guelph, Peterborough, North Bay, Cambridge, Milton, Oakville, Newmarket, Cornwall, Brantford, and Midland. Just type the name or postal code.
Snow Day Frequency by Ontario Region
Northern Ontario cities like Sudbury and Thunder Bay close schools most often, about 8 to 12 times a year. The Greater Toronto Area closes least, roughly 2 to 5 times a year. The difference comes down to snowfall, cold, and how long the bus routes are.
| Region | Typical closures/year | Main driver |
|---|---|---|
| Northern (Sudbury, Thunder Bay) | 8–12 | Heavy snow, long rural routes |
| Central (Barrie, Simcoe County) | 6–10 | Georgian Bay lake-effect snow |
| Eastern (Ottawa, Kingston) | 5–8 | Ottawa Valley storm track |
| Western (London, Hamilton) | 3–6 | Lake Huron and Lake Erie squalls |
| GTA & Southern (Toronto, Windsor) | 2–5 | Strong road crews, milder lake air |
These are typical ranges, not promises. A single bad storm can push any region above its average in one week.
How Ontario School Boards Decide on a Snow Day
Most Ontario boards check road conditions before sunrise. Transportation groups start driving routes around 4:00 to 5:00 a.m., bus drivers report back, and a final call usually lands by 6:15 a.m. For overnight storms, some boards give an early heads-up around 10:00 to 11:00 p.m. the night before.
Each board makes its own call. Public and Catholic boards that share bus routes often close together, since they share the same transportation group. French-language boards sometimes decide differently. Here are boards Ontario families ask about most:
GTA boards
TDSB, TCDSB, Peel (PDSB), York Region (YRDSB), Durham (DDSB), and Halton (HDSB) serve dense city areas with strong plowing.
Eastern & French boards
OCDSB, OCSB, CECCE, and CEPEO cover Ottawa. Kingston’s Limestone board (LDSB) sits nearby.
Western & central boards
TVDSB (London), HWDSB (Hamilton), WRDSB (Waterloo Region), SCDSB (Simcoe County), Grand Erie (GEDSB), and DSBN in Niagara.
Want the full step-by-step process? Read our guide on how schools decide snow days in Canada.
How Much Snow Is Needed for a Snow Day in Ontario?
There is no fixed rule, but about 15 centimetres of snow, or a wind chill near minus 35 degrees Celsius, are the numbers Ontario transportation groups often point to. Each board weighs these against its own roads and history, so the same 10 centimetres can mean a normal day in Barrie and a big problem in Toronto.
Snow amount is only part of it. More than half of all closures come down to road and bus safety, not the snow total on your lawn. Timing matters too: snow that falls during the 4:00 to 7:00 a.m. bus window is far more likely to close school than the same snow arriving at noon. Ice, freezing rain, and blowing snow that cuts visibility can also close schools with very little accumulation.
What counts as a snow day in Ontario? It is a day the school itself is closed because winter weather makes it unsafe to open or to run buses. That is different from a bus cancellation, which we explain next.
Bus Cancellations in Ontario: Regional Patterns
In Ontario, a bus cancellation is far more common than a full school closure, and how often it happens depends heavily on where you live. For the general definition of a snow day versus a bus cancellation, see our national forecast tool.
🚌 Bus Cancellation
Buses are pulled for the day. School stays open. Bus riders are excused with no penalty. This is the most common winter outcome.
❄️ Snow Day (Closure)
The whole school shuts. No students or staff attend. Less common than a bus cancellation.
🔎 Check Both
On a stormy morning, look up your board for both a bus notice and a closure notice. They are separate calls.
Long, exposed rural routes are the reason buses get pulled first. See our school bus safety tips for winter routes.
Does Ontario Get a Lot of Snow?
Yes. Most of Ontario gets real winter snow from about December through March. Snowbelt areas near Georgian Bay and Lake Huron can pile up 300 centimetres or more in a season, while milder southern cities like Windsor and Toronto see far less.
The snowiest spots sit downwind of the Great Lakes, where lake-effect snow forms. Cold air moves over warmer lake water, picks up moisture, and dumps it as heavy, narrow bands of snow. Barrie, Owen Sound, and the Bruce Peninsula are classic snowbelt zones. Northern cities like Sudbury and Thunder Bay get long, cold, snowy winters driven by latitude more than lakes. Southern Ontario near Lake Erie stays the mildest.
Do Ontario Colleges and Universities Close for Snow?
Sometimes, but they close far less often than K–12 schools. Colleges and universities like Ontario Tech, Western, and others make their own weather calls, and many shift to online classes instead of closing fully. Always check the school’s own website or alert system.
Post-secondary students mostly drive or take transit, so a bus cancellation that closes elementary schools may not affect a university at all. When a campus does close, it usually posts the news on its homepage and social media early in the morning.
Best Time to Check Your Ontario Snow Day Forecast
Check around 9:00 p.m. the night before a storm for a first read, then again between 5:00 a.m. and 6:15 a.m., which is when most Ontario boards make their final call. The early-morning check is the most accurate because the overnight snow has already fallen.
Forecasts sharpen as a storm gets closer. A score three days out is useful for rough planning, but the number you get the morning of is the one to trust. Learn more about the best times to check your forecast, or see how prediction tools compare.
Why Trust This Ontario Forecast
Ontario roads, Ontario boards. The score reads live weather for your exact location and lines it up with how nearby boards have handled past storms, instead of a one-size-fits-all number.
Clear about the limits. This is a planning tool, not an official notice. The final word on any snow day or bus cancellation always comes from your school board and its transportation group.
Built for families. Free, fast, and no sign-up. Read our closure guide, learn about the effect of snow days on learning, or head back to the national snow day tool.