Snow Day Predictor MarkhamWill school be cancelled tomorrow in Markham?

Type your Markham postal code or "Markham, Ontario" into the predictor above. The York Region District School Board (YRDSB) makes closure decisions for the entire region, so a closure in Markham also applies in Vaughan, Richmond Hill, Newmarket, Aurora, and the rest of York Region. YRDSB tends to close more readily than the Toronto District School Board because York Region bus routes are longer and the snow squall corridor produces heavier snowfall than the Lake Ontario shoreline.

For the official call, check the York Region Student Transportation Services (STSYR) bus delay portal or the YRDSB and YCDSB social media feeds. STSYR announces bus cancellations in the early morning and the call applies to the entire York Region network, covering Markham, Vaughan, Newmarket, Aurora, Richmond Hill, Whitchurch-Stouffville, and East Gwillimbury. Our predictor gives you an advance probability the night before based on the overnight forecast.

Three reasons. First, Markham sits in the York Region snow squall corridor, a north-south band that runs from Aurora through Stouffville and catches squalls inland of the lake. Second, the Oak Ridges Moraine north of Markham forces air to rise, cool, and drop additional snow on storm tracks that only deliver flurries to the Lake Ontario shore. Third, Markham is far enough inland to lose the lake’s warming effect on cold nights, which lets precipitation fall as snow rather than mixed types. The same Colorado low can drop 5 cm on downtown Toronto and 18 cm on Stouffville with Markham caught in between.

YRDSB and YCDSB make closure decisions at the regional level rather than by neighbourhood, so a closure in Unionville, Cornell, Cathedraltown, Berczy Village, Thornhill, Milliken, or Box Grove will apply to all Markham schools and across York Region. Enter your specific Markham postal code in the predictor for the most accurate overnight forecast at your exact coordinates, particularly important in eastern Markham where the Rouge Valley can shift precipitation type and accumulation totals over short distances.

Usually but not always. The York Catholic District School Board (YCDSB) makes its weather decisions independently of YRDSB, though the two boards coordinate informally and share STSYR transportation. In practice the boards close together on roughly 90% of weather days. The occasional split happens when one board reads a marginal forecast differently, or when a closure call hinges on a specific bus operator’s ability to staff routes. STSYR bus cancellations apply equally to both boards regardless of whether buildings stay open.

The corridor is a north-south band, roughly 30 km wide, that runs from Aurora through Whitchurch-Stouffville and into northern Markham. When upper-level winds come out of the northwest or north, snow squalls organize along that band and stall, dumping 15-25 cm in a few hours while areas to the east and west see flurries. The corridor is enhanced by the Oak Ridges Moraine elevation and by the inland position that loses the lake’s warming influence. The corridor activates on roughly 5-8 days each winter and accounts for a disproportionate share of York Region snow day closures.

Markham averages roughly 20-30% more annual snowfall than downtown Toronto, runs 2-4 °C colder on clear winter nights, and sits in the York Region snow squall corridor that the Lake Ontario shoreline misses entirely. The practical effect on school days: York Region closes and cancels buses more frequently than Toronto in the same season, often on storms that leave downtown Toronto operating normally. If you moved to Markham from Toronto, expect more snow day closures and more bus cancellations through STSYR than you saw under TSTG in Toronto.