A warm signal at 60 meters: reading Monterey Bay’s El Niño observations

A local signal in a long record

On 29 October 2026, MBARI reported that the M1 mooring in Monterey Bay had measured 18.18°C at 60 meters on 26 October. That exceeded the previous high in its nearly 40-year record, set during the 1997 El Niño. MBARI also described the reading as more than seven degrees Celsius above its long-term average. The date attached to the measurement matters: this is a specific observation, not a forecast or a coastwide average. [1]

The mooring sits above the mouth of Monterey Canyon, with instruments along a line from the surface to 300 meters. Its measurements can show how conditions change at particular depths over time. At 60 meters, the reported temperature is especially useful because it lies near the thermocline, the transition zone across which temperature changes rapidly with depth. A record at that level does not mean every layer of the bay warmed by the same amount. [1]

What a mooring can and cannot establish

A fixed instrument is valuable because it observes repeatedly at one place. A single reading might reflect a short-lived fluctuation; a sustained trace can be compared with earlier years and seasonal cycles. MBARI’s report gives both the date and historical context, allowing readers to see why the 18.18°C measurement stands out. The long baseline is the evidence for calling it a record, rather than the absolute temperature alone. [1]

But a record is still a local measurement. The M1 sensor samples one point in a moving ocean. Currents can carry water past it, and nearby slopes, canyons, winds and upwelling shape regional conditions. The observation is consistent with El Niño’s arrival in Central California, as MBARI interprets it alongside equatorial Pacific monitoring and biological sightings. It cannot by itself identify every process contributing to the reading or predict conditions at another beach, depth or date.

A record-high October 2026 temperature at MBARI’s Monterey Bay M1 mooring, interpreted in the context of El Niño forecasts and ecological observations. Research notes.

Connect the bay to the basin carefully

El Niño is a coupled ocean–atmosphere pattern in the tropical Pacific, not a local warm-water label. NOAA’s 8 October diagnostic discussion reported continued strengthening, including an unusually deep equatorial thermocline and a forecast favoring a strong-to-very-strong event through early 2027. It also stated that impacts associated with El Niño become more likely with a larger event but are not guaranteed. This basin-scale assessment provides climate context; it is not a direct validation of the later Monterey reading. [2]

The distinction helps prevent a common reasoning error: treating a prediction and a local observation as if they were the same evidence. Forecasts describe probabilities about future climate conditions. A mooring records what passed a sensor. When the forecasted pattern and a local anomaly align in time and physical context, the combination strengthens the interpretation, while continued measurements are needed to track how the local signal develops.

Biological sightings are clues, not a census

MBARI also reported observations of tropical and southern species, including a winged comb jelly, a rose siphonophore and halfmoon fish. In deeper-water surveys, researchers noted juvenile pelagic red crabs farther north than previously observed by their team. Such records can reveal changes in who is present, but sightings depend on where and when people or vehicles look, the animals’ visibility, and survey effort. An unusual sighting is a useful detection, not a measurement of abundance or proof that a population has permanently shifted. [1]

The ecological interpretation becomes stronger when physical and biological records are connected over time. Temperature and oxygen sensors describe conditions; repeated vehicle surveys document organisms; plankton and chlorophyll observations can indicate changes in the food supply. If each record keeps its location, depth, timing and method, researchers can ask whether species arrivals follow the water-mass change and whether those arrivals persist. MBARI says it is expanding observations to examine impacts from the surface into deep-sea communities. [1]

A practical way to follow the evidence

For a reader following the event, separate four kinds of statement: the sensor reading and its date; the historical comparison used to call it a record; the climate interpretation linking it to El Niño; and projections about future ecosystem effects. Each step relies on more interpretation than the one before it. Record the station, depth, time window and comparison period when discussing a temperature anomaly, and check whether a later report refers to the same sensor and metric.

The 26 October value is an important early indicator for Monterey Bay, not a complete account of the coming season. A long-running mooring makes an unusual change visible against natural variability; regional climate monitoring explains why that change may fit a basin-scale event; and biological surveys can test what follows. Keeping those evidence streams distinct makes the developing story easier to update as the ocean continues to be observed.