Frost already landing in Ontario and here's the latest winter weather forecast

Citizens of Toronto and elsewhere in Ontario are on the lookout for the first frosts of the season this week as temperatures drop from the summery near-30s we saw in recent days to figures far more October-appropriate.

Environment Canada issued frost advisories for GTA locales such as Vaughan, Markham, Newmarket and Richmond Hill on Wednesday, warning that thermometers were set to creep below the zero-degree point overnight into Thursday morning, and again Thursday night into Friday.

While those in rural areas are bundling up any sensitive outdoor plants due to the sudden shift in weather, here in the city, Toronto Pearson International Airport has officially started de-icing some outgoing flights for the first time since last winter.

If you love autumn, this settling-in of the spookiest, most colourful season of the year is likely great news. But, it may also have you wondering what's on deck, meteorologically, as we move toward the end of the year.

According to an updated outlook from The Weather Network (TWN), with the exceptions of a few blips later this month, the unusually warm conditions much of Canada witnessed through September and the beginning of October are coming to an abrupt end.

Though there's a potential for a few "periods of warmer-than-normal temperatures" this month, TWN notes that "quick shots of colder weather will help to prepare us for what is to come" in a far more frigid November.

"We expect a rather abrupt transition into the start of winter [come November," the agency wrote on Wednesday, adding that though "the exact timing is still uncertain, once the warm pattern breaks, we expect near-normal and, at times, colder-than-normal temperatures to stick around for much of December."

This is due to a weak La Niña pattern, which is likely to bring with it some stubborn cold for much of winter this year, primarily in the centre of the country.

But, TWN's meteorologists note that La Niñas can be unpredictable, and that multiple somewhat conflicting factors at play make things hard to determine this far out.

It’s been an exceptionally warm start to fall across many parts of Canada, but will this trend linger into winter 2025-2026? #WinterSneakPeekhttps://t.co/yh72110CqO

— The Weather Network (@weathernetwork) October 8, 2025

What they are confirming at this point, though, is that temps should hover at or below what is normal for the time of year throughout the course of Winter 2025-2026, especially, as mentioned, from eastern Alberta to northeastern Ontario and the western edge of Quebec.

That being said, Southern Ontario is anticipated to experience a "significant stretch of milder weather during the heart of the season," and will also be the stage for the nation's dominant storm track around the Great Lakes Region, which could spell some very messy, snowy weather at times.

However, the weather will vary from week to week, with the fluctuating temperatures of the "wild card" North Pacific Ocean still having the potential to shake things up from current forecasts.

Back in August, the experts at the Farmers' Almanac released their premonitions for the winter season, calling for "traditional winter patterns" running the gamut of deep freezes, snowfalls and strong storms with cold temperatures and an abundance of snow in Ontario specifically.

The Old Farmer's Almanac forecast that dropped just afterward says Canada's winter will be "mostly wet and mild," but with "snowy stretches, chilly snaps, and the occasional polar surprise," especially in Ontario, where below-normal temperatures are expected.