Northern and central Ontario could see their first flurries as early as Oct. 8, according to recent weather models — just two weeks out at the time the forecasts circulated. Southern Ontario, including Toronto, has a longer runway, with several weeks of mild, dry fall weather expected before anything meaningful falls from the sky.
The big story this season is El Niño. The World Meteorological Organization confirmed in September that a "supersized" El Niño is locked in and intensifying toward a very strong event, with a 100 per cent chance it persists through February 2027. For anyone new to the term: El Niño is a natural pattern of unusually warm Pacific Ocean surface temperatures that shows up every two to seven years and rewrites weather patterns thousands of kilometres away — including across Canada.
Counterintuitively, El Niño autumns in Ontario tend to run cool. The Weather Network explains that a trough typically parks itself over the province while a ridge dominates the West Coast, producing colder conditions in the east and warmth in the west. Looking at historical data, the GTA has averaged below-normal fall temperatures during the seven strong El Niño autumns of the past 75 years — October mean temperatures came in 1.3 C below average. That cool autumn could push the first snowfall early: Toronto's typical first measurable snow date is Nov. 11, but during strong El Niño years it slides to Nov. 3.
Here's the twist for anyone planning a ski weekend or a winter city break: an early first flurry doesn't mean a snowier season. The cool autumn pattern usually breaks by December, and in Toronto, strong El Niño Decembers have averaged a full 2.6 C warmer than normal — The Weather Network calls it a "late onset" to real winter. Precipitation-wise, El Niño falls in Toronto have historically run about four per cent rainier and 11 per cent less snowy, with no strong overall trend. So the early dusting may be a false alarm for winter lovers, while anyone dreading shovelling can take some comfort in a likely milder December.
For travellers, this matters if you're timing a trip. Leaf-peepers heading to Ontario's cottage country or Algonquin in early October should pack layers and maybe a warm jacket — northern routes could catch flurries well before Thanksgiving. Toronto visitors in November shouldn't be surprised by an early dusting, but December trips may actually be milder than usual, which is good news for urban explorers, less so for anyone chasing snow.
The takeaway: expect an early teaser of winter up north and possibly in the south too, but don't book your ice-skating plans around it just yet. The season's real character will depend on how this El Niño plays out once December arrives.
