How to Prepare for El Niño: A California Home Checklist

To prepare for El Niño in California this winter, finish four jobs before the first big storm. Have the roof inspected, clear the gutters and downspouts, drain water away from the foundation, and decide on flood insurance, since a new federal policy usually takes 30 days to start. NOAA's October 2026 forecast favors a wetter than normal winter for much of the state. In the 1997-98 El Niño winter, landslides did over $150 million in damage in the Bay Area.

In a Nutshell

• The forecast: NOAA expects a strong El Niño through January to March 2027, at better than 83% odds, and favors above-normal rain for much of California this winter.
• The history: in the nine strong El Niño winters since 1957, Los Angeles, San Francisco, San Diego and Sacramento finished above normal in 28 of 36 city-winters. Across all years since 1951, that happens about 40% of the time.
• The catch: 2015-16 had the highest peak of them on NOAA's traditional Oceanic Niño Index, and Downtown Los Angeles got 48% of its normal rain.
• The order of work: the flood insurance decision first, because of the 30-day wait, then roof, gutters and grading. Kitchens and bathrooms can run through the winter. Exterior and hillside work should finish before the rain or wait for spring.

Is El Niño coming to California this winter?

It is already here. NOAA's Climate Prediction Center has an El Niño Advisory in effect, which means El Niño conditions are present now. On October 8, 2026 it put the odds of a strong El Niño lasting through January to March 2027 at better than 83%, and its October 15 update put the same call at 80%.

That October 15 update is NOAA's El Niño forecast for the winter, and for California it leans wet. It favors above-normal precipitation for much of California and the Southwest from November through January.

The ocean numbers explain why the headlines have started saying "super El Niño." The October ENSO discussion reported sea surface temperatures more than 4°C above normal in parts of the eastern equatorial Pacific. NOAA puts the chance that this becomes a historic event, stronger than any El Niño measured since 1950, at 83% for October to December and 70% for November to January.

Even NOAA hedges its West Coast call. Its seasonal outlook gives the West Coast lower odds than the Southeast, because the models disagree more here. A strong El Niño loads the dice. It does not roll them.

Does El Niño mean more rain in California?

Usually, and most reliably in Southern California. Since 1957 there have been nine winters when NOAA's Oceanic Niño Index peaked at 1.5 or higher. In those winters, the main NOAA stations in Los Angeles, San Francisco, San Diego and Sacramento finished the water year above their 1991 to 2020 normal 28 times out of 36. In all years since 1951, the same stations beat normal only 36% to 42% of the time.

Here is every strong El Niño year in California since 1957, station by station. The most recent was 2023-24.

Water-year rainfall (October to September) as a percentage of each station's 1991 to 2020 average. NOAA station records via the Applied Climate Information System, peak ONI from the NOAA Climate Prediction Center. Compiled by The Renology, October 2026.

The full record, in inches and on both of NOAA's El Niño indexes, is in El Niño years in California: rainfall since 1957.

Two winters show how far apart El Niño years can land. In 1997-98, Downtown San Francisco recorded 46.56 inches, about double its normal. The USGS counted over $150 million in landslide damage across the 10-county Bay Area in the winter and spring of 1998. In 2015-16, the highest peak in the table, Downtown Los Angeles recorded 6.88 inches.

Southern California is where the pattern holds best: Los Angeles and San Diego beat normal in eight of nine strong winters. Northern California is less predictable, with San Francisco above normal in seven and Sacramento in five.

And a season total says nothing about how hard any single storm hits, which is what does the damage. That part depends on the house.

How do you prepare for El Niño, and what should you fix first?

Start with one decision and three repairs. The decision is flood insurance, because of its waiting period. The repairs follow the path water takes off a house: roof, then gutters and downspouts, then the ground around the foundation. When one fails, it overloads everything below it.

The full rainy-season checklist:

For household items, use Listos California's El Niño page. This list is about the house.

The roof is the first repair because it usually needs a licensed roofer and a place on a calendar, while most of the rest can start this weekend. An inspection tells you whether you are paying for a repair or a replacement.

Grading has a code number. Section R401.3 of the 2022 California Residential Code requires the ground to fall six inches within ten feet of a foundation. Where a wall is in the way, drains and swales do the job instead, as Orange County Public Works quotes the rule. Soil piled against the stucco reverses that fall.

Pick up sandbags early. The LAFD hands out up to 25 free sandbags per household at neighborhood fire stations, and San Diego County lists free sand and bag sites. Supplies can run short when demand is high, so go before heavy storms are forecast.

Why book a roofer before the rainy season instead of after the first storm?

Because fall is already the busy season for reroofs, at least in the one California city whose permit record shows it. In San Francisco, 27,864 permits on single-family homes and duplexes whose description names a reroof were filed from 2014 through 2025. August, September and October carried 31% of them. December and January carried under 14%.

A reroof permit is usually pulled shortly before work starts, so a fall filing peak suggests those jobs were arranged weeks earlier. The record cannot show how long any roofer's calendar runs. It does show that homeowners who wait for the first leak are joining the season late, not early.

For budgeting, the Renology Cost Index puts roofing and siding work at $15,000 to $29,000 in California in 2026, with Los Angeles at $17,000 to $26,000 and San Diego at $15,000 to $24,000. In San Francisco, the declared reroof permit median has held at $15,000 for 2024, 2025 and 2026.

The same index puts a roofing and siding project at one to three weeks of work. Ask every bidder for a start date in writing, because this month that date matters as much as the price. For the Central Valley version of this question, see the Sacramento timing trade-offs.

Check the license before anyone climbs a ladder. Since January 1, 2025, work totaling $1,000 or more in labor and materials must be done by a contractor licensed by the CSLB. Smaller jobs need one too if they require a permit. The board also warns that unlicensed contractors target disaster areas, and contracting without a license in a declared disaster area is a felony.

Should you start a renovation before El Niño, or wait until spring?

It depends on whether the work is outside or inside. Exterior work that opens the house to weather or moves soil belongs before the storms or after them. Interior work that stays inside a closed, weathertight house, like most kitchen and bathroom remodels, can usually run through an El Niño winter.

If a project is already underway, ask the contractor three things this week: how the roof or open walls get covered when rain is forecast, who pays if a tarp fails, and how rain days are handled in the schedule. Put the answers in writing, in the contract or a change order.

Grading projects in Los Angeles also run on a legal calendar, and hillside lots get the closest look. The city's building code, LAMC section 91.7007.1, defines October 1 to April 15 as the rainy season. In that window, grading over 200 cubic yards on a permitted site cannot begin until an erosion control system is approved. Hillside owners with unfinished grading of that size must file erosion control plans before October 1, unless the grading inspector exempts them.

For the indoor projects that fit a wet winter, the Cost Index has current ranges for kitchens and bathrooms. For the outdoor ones to plan now and build in spring, see driveways and hardscape and ADU construction.

Does homeowners insurance cover El Niño flooding and mudflows?

Usually not. FEMA's flood program states that most homeowners and renters policies do not cover flood damage, and the California Department of Insurance lists flood, earth movement, landslide and mudflow among the standard exclusions. Flood coverage is a separate policy, and a new federal policy generally takes effect 30 days after purchase.

That waiting period is why the insurance call comes before the roof. A federal policy bought on October 16 would generally start around November 15. FEMA's buy-a-policy page lists the narrow exceptions, such as buying while taking out or refinancing a mortgage.

The federal definition of flood includes mudflow caused by flooding. It does not include every slide or slump of earth. After a wildfire, the Department of Insurance notes, a mudflow can sometimes be covered under a homeowners policy when the fire was the main cause. That depends on the facts of each loss.

This is general information, not insurance advice. Ask your agent, in writing: "Does my policy exclude flood and mudflow? What would flood cover cost here? When would it start?"

What changes if you live below a Los Angeles burn scar?

Everything above still applies, plus one more risk: debris flows from the slopes burned in the January 2025 Palisades and Eaton fires. LA County Public Works says debris flow problems generally exist for several years after a burn. The USGS says burned slopes are most susceptible in the first year, with some producing debris flows for several years.

The county's Homeowner's Guide for Flood, Debris, Erosion Control is the document to read first, and it is specific. Sandbags usually last only one season. Where the county places K-rail along a street, it leaves gaps for driveways, and closing those gaps is the homeowner's job. Deflection walls should be designed by a licensed engineer.

Public Works also offers free engineering advice to property owners in areas at risk of mud and debris flows, one of the most useful local resources on this list. Use it before hiring anyone to build on a slope.

The step that matters most here is not about the house. Sign up for county alerts, know your route out, and do not stay when an evacuation order is issued. A house can be repaired.

The Renology Take

The forecast is the least useful part of this story. The table above is the honest correction to the headlines. Strong El Niño winters usually soak Southern California, yet 2015-16, the highest peak on NOAA's traditional index, left Los Angeles at half its normal rain. Nobody can tell you in October which kind of winter this will be.

That is exactly why the forecast should not decide what you do.

A clogged downspout, a cracked boot around a vent pipe and soil piled against the stucco are problems in any wet winter. In the 76 water years behind that table, Downtown Los Angeles beat its normal 32 times, and most of those were not strong El Niño years. Treat 2026 as the reminder, not the reason. Do the boring jobs now, while they are still boring.

Methodology

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

Rainfall. Monthly precipitation for Los Angeles Downtown (USC), San Francisco Downtown, San Diego International and Sacramento Executive Airport 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, about 14.2 inches for Los Angeles. Strong winters are those whose Oceanic Niño Index peaked at 1.5 or higher between July and the following April, per the NOAA ONI table.

Caveats: on NOAA's newer relative index, which the 2026 historic threshold uses, 1982-83 ranks above 2015-16 and 2023-24 drops below the strong cutoff. On a July to June season, Los Angeles 2015-16 reads 68%, not 48%. San Francisco 2023-24 is missing some daily observations. Downtown gauges do not capture foothill and mountain rain, which can differ sharply.

Permits. San Francisco Department of Building Inspection permits from DataSF, filed January 2014 through December 2025, existing use single-family or two-family dwelling, description naming a reroof or roof replacement. The match misses some reroofs described in other words and includes some permits later cancelled or withdrawn. 2026 is excluded because the dataset's counts drop sharply from July 2026.