Fall in Canada: Mild Weather Before an Abrupt Winter Shift

The Weather Network’s seasonal forecast predicts a calm and mild start to fall in Canada, but warns of a sudden shift to wintry conditions by November.

September has already brought extremes — record-breaking heat in British Columbia and early cold in Ontario and Quebec. Yet, according to senior meteorologist Doug Gillham, the coming weeks will bring a “pause,” with warmer conditions and fewer storms.

“In the typical fall roller coaster, it will be the mild stretches that dominate, giving Canadians a chance to enjoy fall colours and outdoor activities,” Gillham said.

By November, however, more active weather is expected. Storm systems will likely bring near-normal precipitation, with above-normal amounts along the B.C. coast, in Northern Canada, and from northeastern Ontario through to Labrador.

For the Prairies, this is welcome news after a summer of drought. Atlantic Canada, however, remains uncertain: hurricane season is not over, and a single storm could significantly change conditions.

Ontario and Quebec are forecast to enjoy several weeks of warmth before stormier weather returns in November, marking the seasonal transition. The Prairies will see a similar pattern — warmth interrupted by cold snaps, before winter sets in firmly.

In Western Canada, wildfire risks will persist for several more weeks. Rainfall remains limited and temperatures above normal. Only later in the season will rain and snow bring relief.

“We can’t hold off the season forever,” Gillham said. “By late fall, the jet stream will shift southward, and arctic air will reach Canada more frequently.”

Government data shows that average fall temperatures in Canada have risen by 2.4 °C since 1948, shaping today’s forecasts.