El Niño and La Niña are the warm and cool beats of a single planetary oscillation — the largest driver of year-to-year climate on Earth. This is its live pulse, its century-long memory, and an honest look at what comes next.
The Oceanic Niño Index is the official heartbeat trace of ENSO: a three-month running average of sea-surface temperature in the central Pacific. Red beats are El Niño; blue beats are La Niña. Drag to explore seven decades of the ocean's pulse.
A warm tongue of water on the equator shifts the planet's rainfall, droughts, and storms tens of thousands of kilometers away. These are the canonical winter tendencies of a strong El Niño — probabilities, not certainties. Tap a region.
This module projects the index forward with a transparent statistical method — damped persistence, the standard scientific benchmark — and widens its uncertainty across the notorious spring predictability barrier. For official outlooks, it defers to NOAA/IRI and the Bureau of Meteorology.
ENSO is a coupled instability of ocean and atmosphere. Three ideas explain almost everything you see above.
Normally, easterly trade winds drag warm surface water westward, piling it into the Indo-Pacific Warm Pool. Cold, nutrient-rich water wells up off South America. The atmosphere's Walker circulation rises in the west, sinks in the east.
A burst of westerly wind weakens the trades. Warm water slides east as a Kelvin wave, deepening the thermocline and shutting off upwelling. Warmer water weakens the winds further — a self-amplifying loop that locks in the warm phase.
El Niño drains warm water poleward, depleting the equatorial heat reservoir. Reflected Rossby and Kelvin waves return to flip the sign. Depleted, the system swings toward La Niña — which is why the pulse oscillates every 2–7 years.
Built on open, authoritative climate data. When deployed with the included data pipeline, the leading edge of every series refreshes automatically on each source's natural cadence.