El Niño Years in California: Rainfall Since 1957

California has had nine strong El Niño winters since 1957, and in 28 of 36 city-winters the rain came in above normal at the main NOAA stations in Los Angeles, San Francisco, San Diego and Sacramento. Across all years since 1951, those stations beat normal 36% to 42% of the time. The biggest exception, 2015-16, left Downtown Los Angeles at 48% of normal. In 1997-98, by contrast, Bay Area landslides did over $150 million in damage.

In a Nutshell

• The record: nine strong El Niño winters since 1957, four cities, 36 city-winters, 28 above normal.
• The base rate: in all 76 water years since 1951, the same stations beat normal 36% to 42% of the time.
• Most reliable: Los Angeles and San Diego, above normal in eight of nine strong winters.
• Least reliable: Sacramento, above normal in five of nine.

Which years were strong El Niño years in California?

Nine winters since 1957 had a peak Oceanic Niño Index of 1.5 or higher, NOAA's traditional measure of El Niño strength: 1957-58, 1965-66, 1972-73, 1982-83, 1991-92, 1997-98, 2009-10, 2015-16 and 2023-24. The last strong El Niño in California was 2023-24. The two most cited, 1982-83 and 1997-98, were the two wettest of the nine in all four cities.

NOAA now also publishes a relative index, RONI, which adjusts for the warming of the whole tropical ocean. It is the index behind the 2026 "historic event" threshold, and it ranks the same winters differently.

Highest three-month value between July and the following April. NOAA Climate Prediction Center, ONI v5 and RONI tables, accessed October 16, 2026.

On RONI, 1982-83 is the strongest event on record, not 2015-16, and 2023-24 falls below the strong cutoff. Either way, no winter on record has reached a RONI of 2.5, the level NOAA gives 83% odds of crossing between October and December 2026.

How much rain fell in each city during strong El Niño winters?

In inches, water year October through September, with each station's 1991 to 2020 normal in the first row. Downtown San Francisco's 46.56 inches in 1997-98 is the largest total in the set, and Downtown Los Angeles's 6.88 inches in 2015-16 the smallest relative to normal.

NOAA station records via the Applied Climate Information System: Los Angeles Downtown (USC), San Francisco Downtown, San Diego International, Sacramento Executive Airport. Compiled by The Renology, October 2026.

The same numbers as a share of normal:

Does a strong El Niño mean more rain in California?

Usually, and most often in Southern California. Los Angeles and San Diego finished above normal in eight of nine strong El Niño winters, San Francisco in seven and Sacramento in five. In six of the nine winters, at least three of the four cities were above normal.

The base rate is the column most coverage leaves out. Fewer than half of all years beat normal at these stations. Against that, eight of nine is a strong signal. Five of nine in Sacramento is only a modest one.

Which strong El Niño winters were dry?

Four of the nine left at least one city below normal. 1965-66 and 1991-92 were dry in San Francisco and Sacramento while Los Angeles and San Diego ran wet. 2023-24 left Sacramento at 98%, just under normal.

2015-16 is the one that gets remembered. It had the highest peak on the traditional index, 2.6, and was forecast as a wet winter for Southern California. Downtown Los Angeles recorded 6.88 inches, 48% of normal, San Diego 84% and Sacramento 90%, while San Francisco came in at 101%. A NOAA review of that winter concluded that Southern California's seasonal rainfall was below normal despite the forecast.

What does this mean for winter 2026-27?

The odds lean wet, and the record says how far to trust them. NOAA's October 15 outlook favors above-normal precipitation for much of California from November through January, and its October 8 discussion gives better than 83% odds of a strong El Niño through March 2027. History supports a wet Southern California winter in most cases, with 2015-16 as the standing reminder that most is not all.

What that means for the house, and the order to do the work in, is in the companion guide: how to prepare for El Niño in California. If the roof is the worry, the California roofing guide covers materials and cost.

The Renology Take

This table should calm people down and get them moving at the same time. It calms because the most dramatic forecasts are not new: California has been here nine times since 1957, and most of those winters were wet without being 1997-98. It gets people moving because the odds are real: five of the nine winters were above normal in all four cities.

The number we would put on the fridge is the base rate. Around 40% of all years beat normal at these stations, and in Los Angeles 24 of the 32 wetter-than-normal years since 1951 were not strong El Niño winters. A homeowner who only fixes the roof when the headlines say El Niño is preparing for a minority of the wet winters.

Methodology

See the Renology Methodology for how sources are reviewed, ranges are normalized, and planning-data limits are handled.

Rainfall. Monthly precipitation for the four stations was pulled from NOAA's Applied Climate Information System on October 16, 2026 and summed by water year, October through September. Normals are each station's own 1991 to 2020 water-year average. The base rate is the share of water years from 1951 through 2026 above that normal.

El Niño strength. A strong winter is one whose ONI peaked at 1.5 or higher between July and the following April, per the NOAA ONI table. RONI peaks come from the NOAA RONI table, same window. 1987-88 peaked at 1.49 on ONI and is just outside the set.

Caveats. On a July to June season, Los Angeles 2015-16 reads 68% instead of 48%. San Francisco 2023-24 has gaps in the ACIS daily record, with more than three missing days in at least one month. Downtown and airport gauges do not capture foothill and mountain rain, and season totals say nothing about the intensity of single storms, which is what drives flooding and debris flows. Nine events is a small sample.

Reuse. The tables on this page are free to republish and cite under CC BY 4.0, with credit to The Renology and a link to this page. The underlying station and index data are NOAA public records.