Canada's Winter Sneak Peek: El Niño puts record warmth in play

Welcome to the Winter Sneak Peek, Canada! We've looked at the data, and Canada is staring down one of its mildest winters in years, and potentially one of the warmest starts on record.

We have little doubt the season ahead will lean mild. That signal is strong, thanks to a record-breaking El Niño that is expected to peak around the start of winter. The bigger question is how often winter manages to break through—so how wild winter will be remains up in the air.

Official Canadian winter personality: Elusive

Last winter opened with an abundance of Arctic air oozing across the country. This winter will likely begin in almost the opposite direction. It's possible that December could feel more like an extended fall.

Strong El Niño heavily favours warmth. Remember 1997-98, 2015-16, and 2023-24?

The mild start is the highest-confidence piece of the forecast

Winter weather can still break through in sharp bursts

DON'T MISS: Super El Niños can accelerate global sea level rise: study

Winter's two acts: The start vs. the heart

High confidence in a very mild, potentially record-breaking opening act.

Higher impact wintry intrusions are expected, but are unlikely to be long-lasting

The key question is whether El Niño remains dominant. If it fades quickly enough, winter will attempt a comeback or stronger finish.

Even then, it's unlikely that winter will flip the mild script. The question is if it's a blowout (overwhelmingly mild and historic) or simply tips milder than normal.

Three things that will define the season ahead

The wildcards - especially 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.

Portions of Ontario and Quebec could be especially sensitive this winter if storms repeatedly track through while temperatures stay close enough to the freezing mark for snow. Canada's traditionally colder regions and higher elevations can still score heavy snowfall even during a mild winter. Sharp Arctic intrusions and high-impact storms also remain on the table, especially if the polar vortex misbehaves.

The fade that could salvage winter weather

Does El Niño peak a little earlier and weaken rapidly to change the overwhelmingly mild trajectory the season ahead is poised to follow? Does El Niño fade early enough to change the narrative for the final weeks of winter?

Check back with us on November 25 as we offer more clarity on the season ahead.