Ottawa · Ontario · 2026–27 season
Snow Day Predictor OttawaWill school be cancelled tomorrow in Ottawa?
Live overnight forecast for the City of Ottawa, including Kanata, Orleans, Nepean, Barrhaven, the Glebe, and the downtown core. The predictor tunes to OCDSB, OCSB, CECCE, and CEPEO closure patterns, with Ottawa Student Transportation Authority (OSTA) bus cancellation probability returned separately.
Multi-model forecast, five-factor closure engine, province-aware results. No sign-up, no tracking of your queries.
What makes Ottawa unique
Ottawa is the coldest national capital in the G7 by annual mean temperature. Four separate school boards (public, Catholic, French public, French Catholic) plus Ottawa Student Transportation Authority (OSTA) coordinate closure decisions for the city.
Eastern Ontario forecast
Ottawa snow day forecast, what to expect this winter
Ottawa is the coldest national capital in the G7 by annual mean temperature, sitting at the confluence of the Ottawa, Rideau, and Gatineau rivers with no major lake nearby to moderate winter air. Annual snowfall averages around 220 cm, nearly double the Toronto figure, and the city routinely sees overnight lows below −25 °C in January and February. The forecast for any given school day blends snowfall totals, freezing-rain risk, and wind chill, with extreme cold becoming a closure factor in a way it rarely is further south.
School operations in Ottawa are split across four boards: the Ottawa-Carleton District School Board (OCDSB), the largest in Eastern Ontario; the Ottawa Catholic School Board (OCSB); the Conseil des écoles catholiques du Centre-Est (CECCE); and the Conseil des écoles publiques de l'Est de l'Ontario (CEPEO). All four are coordinated for transportation by the Ottawa Student Transportation Authority (OSTA), which means a single OSTA bus cancellation applies simultaneously across English public, English Catholic, French Catholic, and French public routes. Closure announcements typically arrive by 6:00 am the morning of, broadcast through OSTA's portal, board websites, and CBC Radio Ottawa.
For Ottawa families the practical question often combines two signals: whether OSTA cancels buses for the city, and whether any of the four boards close their buildings outright. OSTA cancellations are more common than full closures; the boards typically keep schools open with buses cancelled, similar to the Toronto pattern. Multi-day closures do happen in major storms, ice events, and during polar vortex outbreaks when wind chills drop below −35 °C. Our predictor returns both probabilities so you can plan childcare, work-from-home decisions, and morning commute timing the night before.
School boards
Ottawa school boards we model
The boards and transportation operators that make the morning closure call for Ottawa.
- Ottawa-Carleton District School Board (OCDSB)
The largest school board in Eastern Ontario, serving English public students across the City of Ottawa. OCDSB closure decisions are announced through the board website, social media, and OSTA by 6:00 am.
- Ottawa Catholic School Board (OCSB)
English Catholic schools across Ottawa. Closure decisions typically align with OCDSB on significant weather days, though each board makes an independent call.
- Conseil des écoles catholiques du Centre-Est (CECCE)
French Catholic board covering Ottawa and the wider Eastern Ontario region. Coordinates buses through OSTA, so a transportation cancellation applies in lockstep with the English boards.
- Conseil des écoles publiques de l'Est de l'Ontario (CEPEO)
French public board across Ottawa and Eastern Ontario. Smaller footprint than OCDSB but uses the same OSTA transportation network for bus operations.
Bus transportation
Ottawa Student Transportation Authority (OSTA) coordinates buses across OCDSB, OCSB, CECCE, and CEPEO. A single OSTA cancellation applies across all four boards simultaneously, meaning English public, English Catholic, French public, and French Catholic routes share the same morning weather call. OSTA closure announcements typically arrive by 6:00 am, posted to ottawaschoolbus.ca and broadcast through CBC Ottawa, CTV Ottawa, and board social channels.
Local weather
Ottawa’s signature winter weather patterns
The phenomena that produce most Ottawa snow days.
- Ottawa Valley snow squalls
Localized snow squalls set up along the Ottawa River corridor when cold northwest winds funnel down the valley. Rural areas west toward Arnprior and east toward Rockland often see heavier accumulation than the urban core, with sharp gradients across short distances.
- Colorado low storm track (eastern leg)
Major southern Ontario Colorado lows continue northeast into the St. Lawrence Valley, dropping 20–40 cm on Ottawa in their mature stage. These are the dominant multi-day closure storms, regularly producing the events that shut down OCDSB, OCSB, CECCE, and CEPEO together.
- St. Lawrence freezing-rain corridor
Warm air aloft from Atlantic systems overruns the cold St. Lawrence valley, branching a freezing-rain band into Ottawa from the east. Ice events are less frequent than in Toronto but more damaging when they hit, with the January 1998 Ice Storm as the defining example.
- Polar air outbreaks and extreme cold
Arctic high-pressure systems push polar air into Ottawa several times each winter, producing wind chill values below −35 °C. Boards weigh wind chill heavily in morning calls, since exposed waits for school buses become a frostbite risk in under 10 minutes at those readings.
- Continental winter pattern
Ottawa sits far enough from the Great Lakes that lake-effect moderation is minimal. Winters are colder, drier, and more variable than in the GTA, with longer stretches of sub-zero temperatures and a snowpack that typically holds from late November through late March.
History
Notable Ottawa snow days in recent winters
Storms and ice events that shaped how Ottawa school boards approach the morning call.
February 2008 storm
February 27, 2008A multi-day Colorado low dropped over 40 cm of snow on Ottawa in 36 hours. OCDSB, OCSB, CECCE, and CEPEO all closed; OSTA cancelled all routes; OC Transpo suspended bus service across the city. The storm contributed to one of the snowiest winters on record in Ottawa.
January 2022 winter storm
January 17, 2022A major Colorado low brought 30+ cm of snow and 60 km/h winds to Ottawa overnight. OCDSB, OCSB, CECCE, and CEPEO all closed; OSTA cancelled buses; downtown plowing took several days to fully restore. A textbook modern Ottawa full-closure event.
Great Ice Storm of 1998
January 5-10, 1998A five-day freezing-rain event deposited up to 100 mm of ice on Eastern Ontario, including Ottawa. Power was out for weeks in parts of the region; schools closed for an extended period; the Canadian Armed Forces deployed in Operation Recuperation. The defining weather event in Eastern Ontario history.
April 2018 ice storm
April 14-15, 2018A late-season ice storm coated Ottawa and Eastern Ontario with significant freezing rain and ice pellets over two days, forcing multi-day closures across OCDSB, OCSB, CECCE, and CEPEO. A reminder that Ottawa's snow-day risk extends well into April.
Polar vortex closures
January 30-31, 2019A polar vortex outbreak pushed wind chill values below −40 °C across the Ottawa Valley. OCDSB, OCSB, and the French boards closed schools or cancelled buses across consecutive days, with Environment Canada extreme cold warnings in effect for most of the region.
February 2007 Valentine's storm
February 13, 2007A fast-moving system dropped 40 cm of snow on Ottawa in 24 hours with blowing-snow whiteout conditions. All four boards closed and OSTA cancelled buses; Highway 417 and rural roads were impassable for much of the day.
FAQ
Ottawa snow day frequently asked questions
The 7 questions Ottawa parents and teachers ask us most.
Will OCDSB close tomorrow?
Type your Ottawa postal code or "Ottawa, Ontario" into the predictor above. The Ottawa-Carleton District School Board (OCDSB) makes its weather call by 6:00 am and posts the decision to ocdsb.ca, social media, and through Ottawa Student Transportation Authority (OSTA). Our forecast gives you an advance probability the night before based on the overnight snowfall, freezing rain, and wind chill forecast.
Are OSTA buses cancelled today?
For the official call, check ottawaschoolbus.ca, the OSTA bus delay portal, or CBC Radio Ottawa in the morning. OSTA announces cancellations by 6:00 am, and a cancellation applies simultaneously across OCDSB, OCSB, CECCE, and CEPEO. Our predictor gives you an advance probability the night before so you can plan childcare and commute timing.
How does Ottawa cold (wind chill) compare to Toronto?
Ottawa is significantly colder than Toronto in winter. Mean January temperature in Ottawa is around −10 °C versus −4 °C in Toronto, and Ottawa routinely sees wind chill values below −35 °C during polar air outbreaks, a threshold Toronto rarely reaches. Wind chill is therefore a more important closure factor in Ottawa than it is in the GTA, where snowfall and freezing rain dominate the decision.
Will school be cancelled in Kanata or Orleans tomorrow?
Kanata, Orleans, Nepean, Barrhaven, and the downtown core are all served by the same four boards (OCDSB, OCSB, CECCE, CEPEO) and the same OSTA bus network. A board closure or OSTA cancellation applies city-wide. That said, local weather can vary: Kanata in the west often sees more snow from northwest squalls along the Ottawa River, while Orleans in the east can pick up additional accumulation from St. Lawrence Valley systems. Enter your exact postal code for a forecast at your coordinates.
Do French boards (CECCE, CEPEO) always close with OCDSB?
Not always, though they typically align on major storms. CECCE and CEPEO each make independent closure decisions for their school buildings, but because all four boards share OSTA for transportation, a bus cancellation hits all four at once. On marginal weather days you can see one board close buildings while another stays open, even when buses are cancelled across the board.
Will school be cancelled in Ottawa if Gatineau (Quebec side) closes?
Not automatically. Gatineau schools operate under Quebec's Centre de services scolaire des Portages-de-l'Outaouais and other Quebec boards, with separate closure decisions made independently of Ontario boards. The same storm often hits both sides of the river, so closures frequently coincide, but a Gatineau closure does not by itself trigger an Ottawa closure. Check your specific Ottawa board (OCDSB, OCSB, CECCE, or CEPEO) for the decision that applies to your school.
How does the Rideau Canal area weather differ from Kanata?
The downtown core near the Rideau Canal benefits from a modest urban heat island effect, typically running 1–3 °C warmer than Kanata or the rural fringe in winter. That can mean rain or freezing rain downtown while Kanata gets snow, or a lighter overnight accumulation in the Glebe than in Stittsville. Our forecast pulls hourly data at your exact postal code rather than averaging across the city, so the gradient shows up correctly.
Near Ottawa
Nearby Ontario cities
Other Ontario cities our forecast covers — same regional profile, different local weather.
Looking for forecasts across the rest of Ontario? View the Ontario hub with all school boards, transportation consortia, weather zones, and a full city directory. Or browse the provinces & territories hub for every Canadian region.
Also in Ontario: Mississauga · Brampton · Hamilton · London · Kitchener · Waterloo · Barrie · Windsor · Sudbury · Thunder Bay · Markham · Vaughan
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