El Niño is usually the kiss of death for snowfall in Seattle.

Except when it’s not.

The internet has been ablaze with headlines in recent weeks about how El Niño—the global climate phenomenon that results in warmer ocean temperatures in the equatorial Pacific—is back for the first time in five years. El Niños tend to lead to warmer winters across the northern tier of the U.S.—especially in the Seattle metro, where the extra dose of warmth usually squashes our chances for any meaningful snow.

That must mean the winter of 2018–19—our last El Niño—was nearly snowless in Seattle, right?

Far from it.

Two of Seattle’s snowiest winters were El Niños. Say what?

With a whopping 21.0 inches of snow, the El Niño winter of 2018–19 stormed into the record books as the city’s snowiest winter since 2008–09, when a series of December snowstorms brought Seattle to its knees. What’s more, during that last El Niño winter, Seattle recorded its snowiest February in over 100 years—and its snowiest month since January 1969.

It’s true that up until the snowpocalypse of February 2019, the city was on track for a historic dud of a winter. Case in point: Until they started flying on Super Bowl Sunday of 2019, Seattle had yet to see a single snowflake, with the preceding January, December, and November all running on the warm side. But then everything changed. February finished as Seattle’s coldest in 30 years and snow still covered the ground in parts of the region well into March. In an El Niño winter, of all winters.

Perhaps even more surprising, the snowmaggedon of five winters ago wasn’t even the most snow we’ve received in a post-war El Niño winter. That honor belongs to the winter of 1968–69. That’s right, the last time Seattle saw more snowfall in a given month than in the El Niño February of 2019 was in the…El Niño January of 1969. Not only that, but the winter of '68–'69 set the all-time record for snowiest winter on record in the existence of Sea-Tac Airport, with a staggering 67.5 inches of snow piling up from start to finish. That’s more than even the legendary winter of 1949–50—which logged 63.6 inches at the airport.

But those weren’t “strong” El Niños…

It goes without saying that there are two sides to every story—and the other side to this one is that both the winters of 2018–19 and 1968–69 were classified as moderate or weak El Niños in terms of their strength. If the latest forecasts hold, the winter of 2023–24 is likely to be a strong El Niño. So, how do strong El Niños typically stack up snowfall-wise in Seattle? Is there a causal relationship between the strength of an El Niño and the absence of significant snowfall?

A look at the data reveals a familiar theme: Usually—but not always. Of the eight El Niño winters since 1950 that meet the definition of “strong,” Seattle was skunked in six of them. As in, the city received zero snowfall. Nada, nothing. But in the other two? Let’s just say things were a bit wintrier.

The winter of 1965–66 (the other winter to not follow the strong El Niño script) saw 22.9 inches total whitening the ground, which is actually slightly more than we saw during the weak-El-Niño “snowmaggedon” winter of 2018–19! Highlights of the winter of '65–'66 included a top-10 daily snowfall (8.9 inches) on Dec. 23 as well as Seattle’s second-snowiest Christmas Day on record.

The odds suggest a mostly snowless winter. But odds ≠ outcome 

Now, to be clear, I’m not arguing that Seattle will defy consensus weather predictions this winter and get walloped by Old Man Winter. The odds are still in favor of a mostly snowless winter in the greater Puget Sound region. The main point here is to stress that the odds don’t tell the full story—and that playing the odds isn’t a foolproof strategy. Mother Nature is fickle, and just because the dice are weighted one way doesn’t mean that’s how they’ll always fall.

Another case in point: Last year was a La Niña winter, which typically spells much drier-than-normal conditions for California—and a soggier-than-usual scene across the Pacific Northwest. But the exact opposite ended up happening. California had one of its wettest winters in decades, while Seattle recorded well-below normal precipitation from January through March.

Now, nearly a year later, we’re on the verge of what’s supposed to be a warm, nearly snow-free El Niño winter. And to be honest, that’s probably how this winter will play out.

Except if it doesn’t.

 Justin Shaw is the author of Seattle Weather Blog.