Ontario's winter could be 'mildest in years' thanks to record-breaking El Niño

Ontario could be headed for an unusually mild winter, according to a new forecast that predicts the province will see well-above-normal temperatures during the early part of the upcoming season. 

The Weather Network officially dropped its winter sneak peek this week, and the long-range outlook suggests that Canada could be headed for one of its "mildest winters in years" and potentially one of the "warmest starts on record." 

The forecast notes that there's little doubt that the upcoming winter will lean mild, thanks to a record-breaking El Niño that's expected to peak around the start of the season. 

For Ontario, including the GTA, that means December could feel more like an extended fall rather than the start of winter, with temperatures expected to range well above normal averages. 

The mild start is the highest-confidence piece of the forecast, but that doesn't necessarily mean harsh winter weather is completely off the table. 

So, what exactly is El Niño? While it directly translates to "little boy" in Spanish, it actually refers to a natural climate phenomenon that's characterized by unusually warm ocean surface temperatures in the central and eastern equatorial Pacific. 

El Niño will continue to intensify ahead of its forecast peak in December. Sea-surface temperatures in central & eastern tropical Pacific are set to increase to record levels. Above-average temperatures globally & shift in rainfall patterns are likely. ↪️ https://t.co/RkalrbYa4Q https://t.co/JkXBOhtYD7

— World Meteorological Organization (@WMO) October 8, 2026

The phenomenon usually occurs every two to seven years and lasts between nine and 12 months. Although it develops thousands of kilometres away from Canada, El Niño has the ability to significantly alter global atmospheric circulation and shift temperature patterns around the world. 

The climate pattern typically begins developing between March and June, reaches its peak intensity between November and February, and this year's event is shaping up to be a significant one. 

In an update on Thursday, the World Meteorological Organization (WMO) said sea surface temperatures in the central and eastern equatorial Pacific are expected to reach record levels between October and December 2026. 

The organization noted that El Niño will continue to intensify ahead of its forecast peak in December, and is expected to bring above-average temperatures to much of the globe while shifting precipitation patterns will increase the risk of drought and flooding different regions. 

"El Niño is firmly established and strengthening rapidly. WMO forecasts indicate a near-100 per cent likelihood that it will persist through February 2027, potentially being one of the strongest since at least 1950," said WMO Secretary-General Celeste Saulo. 

While Ontario's winter is expected to be mild to start off, The Weather Network cautions that the season can still make its signature appearance in sharp bursts. As a result, there is a potential for more impactful winter weather between late January and into February, but any cold snaps are expected to be relatively short-lived. 

The big question remains whether El Niño will stay dominant throughout Ontario's winter. If it fades quickly enough, winter could attempt a comeback later in the season, but if it stays put, we could be in for an overwhelmingly mild, potentially historic winter. 

Ultimately, three factors will define the upcoming season, namely the strength of El Niño, its timing, and a series of wildcards, including the polar vortex. 

"A milder winter doesn't automatically mean a low-impact winter. High-impact storms can still occur, and where temperatures remain just cold enough, an active storm track can deliver significant snowfall," the outlook reads. 

"Sharp Arctic intrusions and high-impact storms also remain on the table, especially if the polar vortex misbehaves."