London Ontario Snow Day Predictor & Calculator
Will TVDSB close tomorrow?
London Ontario sits in the heart of Ontario's snow belt, caught between Lake Huron to the northwest and Lake Erie to the south. Northwest winds drive Lake Huron lake-effect snow directly into London — the same systems that bury Barrie and Owen Sound can still carry significant moisture to the Thames Valley. London averages 200 to 230cm of snow annually, nearly double Toronto's 130cm.
The Thames Valley District School Board covers one of the largest geographic footprints of any Ontario school board — London, St. Thomas, Woodstock, Strathroy, Tillsonburg, Aylmer, and Ingersoll all fall under TVDSB. When TVDSB closes, all 150 schools across this entire region close simultaneously. Rural route conditions in Oxford, Elgin, and Middlesex counties — not London city streets — drive the closure decision.
TVDSB Announcement Window
By 6:00 AM
Check at 9pm for an early read and again at 5am for the final pre-announcement probability. TVDSB announces by 6:00 AM — covers London, St. Thomas, Woodstock, Strathroy, and all of Thames Valley.
London Ontario School Boards — TVDSB & LDCSB
Two school boards serve the Thames Valley region — both cover London and surrounding communities and almost always align on closure decisions.
Thames Valley District School Board
TVDSB covers London, St. Thomas, Woodstock, Strathroy, Tillsonburg, Aylmer, and Ingersoll — 150 schools across a vast region. Rural route conditions in Oxford, Elgin, and Middlesex counties drive the closure decision. One impassable rural route closes all 150 schools simultaneously.
London District Catholic School Board
LDCSB almost always aligns with TVDSB — both boards monitor the same road conditions and typically announce within minutes of each other. Always verify at ldcsb.ca or @LDCSB on Twitter directly.
TVDSB covers all of Thames Valley: If you live in St. Thomas, Woodstock, Strathroy, Tillsonburg, Aylmer, or Ingersoll — this snow day predictor applies to your school. All 150 TVDSB schools close simultaneously when a closure is called.
Verify Here When the Announcement Drops
Always verify from official sources — predictions update hourly but announcements are final.
TVDSB Snow Day Predictor — St. Thomas, Woodstock & Thames Valley
TVDSB is one of the largest school boards in Ontario. When London closes, the entire region closes.
St. Thomas Snow Day Predictor
St. Thomas falls under TVDSB — Elgin County schools close when TVDSB closes London. Rural Elgin County routes are among the first to be declared unsafe in winter storms, often driving the board-wide closure decision. Use this predictor for St. Thomas school closures.
Woodstock Snow Day Predictor
Woodstock is in Oxford County — also under TVDSB. Oxford County rural routes can receive heavier snowfall than London city during northwest Lake Huron events. Use this predictor for Woodstock school closures. TVDSB covers Woodstock, Ingersoll, and all of Oxford County.
Strathroy & Middlesex County
Strathroy and surrounding Middlesex County communities fall under TVDSB. Middlesex County rural routes to the west of London are directly exposed to Lake Huron lake-effect snow bands. When TVDSB closes London, Strathroy and all Middlesex County schools close simultaneously.
One predictor covers all of Thames Valley: Whether you are in London, St. Thomas, Woodstock, Strathroy, Tillsonburg, Aylmer, or Ingersoll — snowdayprediction.ca London Snow Day Predictor applies to your school. TVDSB makes one decision for all 150 schools.
London Ontario Snow Day Patterns
Why London is in Ontario's snow belt — and why TVDSB closes more than Toronto despite similar geography.
Northwest — Lake Huron Lake-Effect
Northwest winds crossing Lake Huron pick up moisture before reaching London. The same systems that produce heavy lake-effect snow in Barrie, Owen Sound, and Kincardine can still carry significant snowfall all the way to London. Lake Huron events are London's primary heavy snowfall driver, typically producing 15 to 35cm in single events.
Southwest — Lake Erie Enhancement
Southwest winds crossing Lake Erie bring additional moisture enhancement to London. While Erie events are typically less intense than Huron events for London, they extend the snowfall season and add to overall annual accumulation. This dual lake exposure is why London averages 200 to 230cm annually versus Toronto's 130cm.
Oxford, Elgin & Middlesex Counties Drive Closures
TVDSB's geographic footprint extends far beyond London city. Rural Oxford County (Woodstock, Ingersoll, Tillsonburg), Elgin County (St. Thomas, Aylmer), and Middlesex County (Strathroy, Strathroy-Caradoc) have long county road bus routes that are far more vulnerable to winter conditions than London city streets. TVDSB closes for the worst rural route, not the average London street condition.
London vs Ontario — School Closure Comparison
TVDSB averages 8 to 10 school closure days per year — more than Toronto (3 to 5), Hamilton (6 to 8), and Kitchener (6 to 8), but fewer than Barrie (12 to 15) and Ottawa (8 to 10). London's dual lake exposure and TVDSB's large rural footprint put it in the upper tier of Ontario school closure frequency.
What to watch for in London Ontario: Northwest wind forecasts combined with Lake Huron moisture are your primary closure signal. Any overnight forecast showing 15cm+ from a northwest system, or a freezing rain warning, is a strong TVDSB closure indicator. Check snowdayprediction.ca at 9pm and again at 5am.
London Ontario TVDSB Snow Day History
Historical TVDSB closure data — what storms actually closed Thames Valley schools and why.
Notable TVDSB Closure Events
The last major TVDSB closure was January 17, 2022, when an Alberta clipper deposited 28cm across the Thames Valley region. TVDSB typically closes when STML cancels buses region-wide, when overnight snowfall exceeds 15cm, or when freezing rain accumulates on rural county roads in Oxford, Elgin, or Middlesex.
Alberta clipper deposited 28cm across London and Thames Valley in 24 hours. TVDSB closed all 150 schools. Highway 401 reduced to one lane near Woodstock. Rural Oxford County roads declared unsafe by 3am.
Early season Lake Huron lake-effect event — 35cm in London in 36 hours. TVDSB closed. One of the largest early-season snowfall events on record for London Ontario.
22cm followed by freezing rain. TVDSB closed both days. Rural Elgin and Oxford county routes declared impassable. St. Thomas and Woodstock schools closed alongside London.
Worst London Ontario winters on record for school closures
2007–2008 · 2014–2015 · 2021–2022 — these winters produced the highest number of TVDSB closure events, with 2014–2015 notable for repeated Lake Huron lake-effect events and multiple back-to-back closure days.
Last Notable London Ontario Storm Event
TVDSB and LDCSB both closed. 28cm across Thames Valley — Highway 401 reduced to one lane near Woodstock, rural Oxford County roads unsafe by 3am.
Tracking London Ontario closures since launch — this card updates after each recorded closure event.
London Ontario Road Conditions
Highway 401 · Highway 402 · Oxford County Roads · Elgin County Roads
Highway 401 near Woodstock and rural county roads in Oxford, Elgin, and Middlesex are the key corridors monitored by STML and TVDSB assessors. When Highway 401 shows ice or closure warnings alongside rural county road reports, a full TVDSB closure is very likely. Check 511on.ca for live Ontario road conditions.
What Do London Ontario Parents Think?
Will TVDSB close tomorrow? Cast your vote — resets daily at midnight.
Community vote — not a prediction. Check the probability gauge above for the algorithm-based forecast.
London Ontario Snow Day Tips for Parents
TVDSB-specific advice based on how Thames Valley school closures actually work.
Watch Northwest Wind Forecasts
Northwest winds over Lake Huron are the primary driver of London's heaviest snowfall events. When the overnight forecast shows northwest winds above 30km/h combined with a precipitation system, prepare for significant snowfall and a higher closure probability. Environment Canada Lake Huron snow squall warnings are a near-certain closure signal.
Rural Routes Close Before City Streets
London city streets may look manageable while rural Oxford, Elgin, and Middlesex county routes are dangerous. TVDSB closes for the worst route across the entire 150-school region — do not look out your window and assume school is open. Always check tvdsb.ca or @tvdsb on Twitter directly before deciding.
AM 1290 CJBK Is the Fastest Source
AM 1290 CJBK and FM 96.7 receive TVDSB notifications simultaneously with the board website. Radio announcements often reach London families faster than website checks during high-traffic storm mornings. CBC Radio One 93.5 FM also broadcasts closure announcements from 6:00 AM.
Check at 9pm and 5am
The 9pm check gives you the best early read — especially important in London where Lake Huron squall events can develop rapidly overnight. The 5am check gives you the most accurate pre-announcement read just before STML and TVDSB assessors report in. TVDSB announces by 6:00 AM.
Thames Valley & Nearby Cities — Snow Day Predictor
Snow Day FAQ — London Ontario & TVDSB
London Ontario questions about TVDSB and LDCSB school closure decisions.
Why does London Ontario get more snow days than Toronto?
London sits between Lake Huron and Lake Erie, receiving lake-effect snow enhancement from both. Northwest winds drive Lake Huron snow directly into London while southwest systems bring Lake Erie moisture. London averages 200 to 230cm of snow annually versus Toronto's 130cm, and TVDSB's large rural footprint means closures happen at lower snowfall totals than Toronto boards.
What time does TVDSB announce school closures?
TVDSB announces by 6:00 AM. The fastest sources are Twitter @tvdsb and tvdsb.ca. AM 1290 CJBK and FM 96.7 also broadcast closure announcements from 6:00 AM.
Does LDCSB close when TVDSB closes?
Almost always. London District Catholic School Board and TVDSB monitor the same road conditions and typically announce within minutes of each other. Always verify at ldcsb.ca or @LDCSB on Twitter directly.
Does TVDSB cover St. Thomas and Woodstock?
Yes — TVDSB covers London, St. Thomas, Woodstock, Strathroy, Tillsonburg, Aylmer, and Ingersoll. When TVDSB closes, all 150 schools across the entire Thames Valley region close simultaneously. The snowdayprediction.ca London Snow Day Predictor applies to all of these communities.
What triggers a TVDSB school closure?
Rural route conditions in Oxford, Elgin, and Middlesex counties are the primary trigger — not London city streets. When STML cancels buses region-wide, TVDSB almost always closes all schools. Snowfall above 15cm overnight and freezing rain warnings are the most reliable closure signals.
Does London get lake-effect snow from Lake Huron and Lake Erie?
Yes — London receives lake-effect enhancement from both lakes. Northwest winds drive Lake Huron snow bands directly into London, while southwesterly systems bring Lake Erie moisture. This dual lake exposure is why London averages significantly more snowfall than Toronto despite similar latitude.