Other strong El Niño years show what California's 2026 winter might look like

No two El Niño years are the same, but one of the best ways to try to figure out what's going to happen this winter is to look back at previous winters that had similar setups going into the season. 

However, scientists only started recording El Niño years and their impacts in 1950, and although there have been 28 El Niño events since then (and 25 La Niñas), only three of those winters saw very strong El Niño events like this year: 1982-82, 1997-98, and 2015-2016. 

The past 28 events on average saw wetter-than-normal conditions across the entire state of California; Southern California saw 110-120% of normal rainfall, while northern CA averaged 100-110%. Weak El Niño events normally see below-average precipitation for the Bay Area, while Southern California still averages above normal. In fact, all of the central and southern coast of California averages wetter-than-normal for moderate, strong, and very strong events. 

For the three very strong events, it's interesting to note the outlier of 2015-2016. Both 1982-83 and 1997-98, Southern and Central California's coast saw around double the usual rainfall, but even though it was forecast to be wetter than normal in 2015-16, the entirety of their coasts was below average. 

So where did forecasts go wrong, and what went wrong? Well, El Niño is not the only factor for winter weather, especially on the West Coast. In 2015-16, there was really warm water in the Indian and western Pacific Oceans, which meant that storms that would normally hit coastal California were pushed further north and brought record precipitation to the Pacific Northwest. That was an effect completely separate from El Niño but still a huge driver for the West Coast's winter weather. 

This year, we are not seeing the warm blob in the Indian/west Pacific oceans, so all signs are pointing towards a wetter-than-normal winter season. There is warmer-than-normal water in the North Pacific, which could shift the jet stream farther south and bring more storms to Southern California, but it's still highly uncertain. 

I have not seen a single forecast that puts any part of central and southern California below average, but as we learned in 2015, El Niño doesn't guarantee anything, and it definitely does not predict where our winter storms and atmospheric rivers will set up. Warmer water evaporates more quickly, which adds more moisture to the air and in turn, should create more intense and heavier rainfall, but exactly where that sets up is still to be determined.