La Niña is officially—and finally—here.
Months of waiting have come to an end as ocean temperatures in the Pacific have now met the criteria necessary to declare an official start to La Niña.
Here’s what this pattern could mean for weeks and months ahead.
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La Niña’s arrival is a long time coming. Experts have been expecting this pattern since last summer.
However, the pattern arrived on its own schedule. Even though atmospheric conditions responded to the change in ocean temperatures as if La Niña arrived in stealth mode last month, it wasn’t until this week that the U.S. Climate Prediction Center (CPC) could announce that it’s officially arrived.
The CPC gives a 60 percent chance that a weak La Niña will stick around through the end of winter, with about the same odds that we’ll revert back to ENSO-Neutral conditions in time for the spring.
La Niña occurs when water temperatures around the equator in the eastern Pacific Ocean come in around 0.5°C colder than normal for several consecutive months.
November 2024: Current La Nina
Even though we’ve just now crossed that threshold, the atmosphere responds to colder-than-normal waters before hitting that temperature benchmark. As a result, we’ve seen weather patterns consistent with La Niña for several months now.
While water temperatures in the Pacific aren’t the only factor influencing our winter weather patterns, overall conditions this season should closely track with what you’d expect to see during a La Niña winter.
North America Temperature Winter 2024-2025
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Forecasters expect overall wintertime temperatures to come in above-seasonal across most of Eastern Canada, while generally below-seasonal temperatures are expected for much of Western Canada.
That’s generally in line with what you’d expect to see during a winter touched by La Niña’s influence.
North America Precipitation Winter 2024-2025
Meanwhile, an active storm track will likely bring above-normal precipitation to much of Ontario and western Quebec as a steady stream of low-pressure systems move across the Great Lakes region.
WATCH: Snowbirds looking forward to a warmer, calmer U.S. winter ahead
Click here to view the video