The ocean off the California coast is running about 10 degrees above normal for mid-November, shattering records along nearly the entire shoreline as an extreme El Niño builds on a long-running marine heat wave. Water near the Farallon Islands off San Francisco has reached 65 to 66 degrees Fahrenheit, against a usual November figure of about 56, according to Scripps Institution of Oceanography shore-station data. Forecasters warn the warm water, with incoming storms and approaching king tides, raises the risk of dangerous surf and coastal flooding.

Key Points

• Sea surface temperatures along much of the California coast are roughly 10 degrees Fahrenheit above normal, peaking near 65 to 66 degrees around the Farallon Islands off San Francisco.
• The warm anomaly runs in one unbroken band from Punta Eugenia in Baja California to the Sonoma County coast, the warmest on record for the date along nearly the whole coast.
• The warmth is record-shattering for any cool-season week from November 1 to April 30 since satellite records began in 1981, from Newport Beach to Eureka.
• Thermal expansion is pushing coastal sea levels at least 6 to 12 inches above average, and warm water plus storms and king tides could bring dangerous surf and flooding.
• Marine life is already stressed, with rare warm-water creatures moving north, including an olive ridley sea turtle that nested on a Ventura County beach on November 1.

What Happened

New data presented at a NOAA and Scripps media briefing on November 12, 2026, shows how far the California coast has drifted from normal. Scripps shore stations recorded water far above the seasonal average up and down the coast, warmest in a band from Punta Eugenia in Baja California to the Sonoma County coast. In many places the water is warmer than any cool-season week on record.

The Farallon Islands, about 30 miles off San Francisco and normally the centre of the region's famously cold upwelling zone, tell the story: 65 to 66 degrees, against a typical November figure of about 56. At Scripps Pier, 53 days in 2026 had set record-high water temperatures by October 20, and Santa Barbara saw 71 record-setting days.

Background and Context

The immediate cause is an extreme El Niño, the periodic warming of the tropical Pacific that shifts weather across North America. NOAA expects strong to very strong conditions from January to March. But El Niño is not acting alone: it is building on a pre-existing marine heat wave amplified by long-term ocean warming, so several factors are stacking.

El Niño winters are typically wetter and stormier for California, and this one is already delivering. A series of Pacific storms is moving in this weekend, bringing heavy rain and waves of up to 30 feet. Warm coastal water adds moisture and energy to those storms. For more on the incoming surf, read our report on California storm waves reaching 30 feet.

California Ocean Record Warmth: Why the Water Is This Hot

Three forces are working together. First, El Niño is warming the tropical Pacific and sending that warmth north along the coast. Second, a marine heat wave was already in place before El Niño strengthened, so the ocean started from an unusually warm baseline. Third, decades of ocean warming have raised the sea's background temperature, so each new warm event starts from a higher floor.

Climate scientist Daniel Swain estimates about 12 inches of the persistent 12 to 18 inch ocean-height anomaly along the coast comes from thermal expansion of seawater. Each coastally trapped Kelvin wave that arrives this season could add another inch or two. The European forecast ensemble suggests a high likelihood the extreme anomalies will persist through at least January or February.

Reactions and Quotes

Swain did not hide his surprise. "Never in our lifetimes has the water been this warm, this late in the season, along the California coast — and in many cases by a considerable margin," he wrote. He said the anomalies made him recheck the data, adding: "I promise that it's real, and corroborated by a growing number of direct and indirect sources and observations."

On the Farallon reading, he posted that temperatures there "now exceed 66F, shattering all records for this late in calendar year" at a spot he called "usually the epicenter of NorCal's infamously frigid upwelling zone". He also warned the implications "are and will be profound". National Weather Service forecasters have urged people to stay out of the water and off jetties and piers as the first big swells arrive.

Why It Matters

Warm water does not stay in the ocean. It raises coastal air temperatures and humidity, feeds extra moisture and energy into incoming storms, and lifts sea levels as the year's highest tides approach. Swain warns water levels during this year's king tide periods will likely run at least one foot, possibly two, above typical levels, and a storm during one of those windows could add another one to two feet. The heat wave has also been linked to seabird die-offs along the West Coast. For context, see our report on the record king tides that flooded California and Florida.

What Happens Next

The immediate threat is the storm series now arriving. The first storms reach Northern California on Friday, with several more waves expected over the next nine days, each bringing moderate to heavy rainfall, gusty winds and possibly isolated thunderstorms. The National Weather Service warns of breaking waves of up to 30 feet off San Francisco, southern Monterey Bay and the Big Sur coast, with sets of 40 to 50 feet possible and surf of 7 to 12 feet near Los Angeles.

Over the longer term, El Niño is expected to keep strengthening, with NOAA forecasting strong to very strong conditions from January to March. Seasonal models are producing some of their wettest forecasts ever issued for California, and the odds of an extremely wet month between December and March remain notably high. Residents in low-lying areas should watch official updates and never drive through standing water. For how the same pattern is fuelling storms elsewhere, read our explainer on the super El Niño that has not peaked yet.

Frequently Asked Questions

How warm is the ocean off California right now? Sea surface temperatures are roughly 10 degrees Fahrenheit above normal for mid-November, peaking near 65 to 66 degrees around the Farallon Islands, against a usual November figure of about 56.

What is causing the record ocean warmth? An extreme El Niño is building on a pre-existing marine heat wave amplified by long-term ocean warming.

How long will the warm water last? Models suggest the extreme anomalies will likely persist through at least January or February, with El Niño peaking around December.

Why does warm ocean water raise flooding risk? Warm water expands, lifting sea levels 6 to 12 inches above average, and adds moisture and energy to storms. With king tides, it can push water over seawalls into low-lying areas.

Is marine life affected? Yes. Rare warm-water creatures are moving north, including an olive ridley sea turtle that nested in Ventura County on November 1, and the heat wave has been linked to seabird die-offs.