ENSO Tracker
Official status of the El Niño–Southern Oscillation

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About ENSO tracker

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The current status of the El Niño-Southern Oscillation (ENSO) is determined by set criteria and expert analysis from Bureau of Meteorology climatologists. The tracker provides an early indication of the possible development of an El Niño or La Niña event, to aid effective planning and preparation prior to an event occurring. It is updated fortnightly.

ENSO status graph, stages are La Niña WATCH, La Niña ALERT, LA NIÑA, NEUTRAL, El Niño WATCH, El Niño ALERT, El NIÑO

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How is the ENSO Tracker status determined?

The ENSO Tracker indicates the likelihood of an El Niño or La Niña occurring using a three-stage system. The status of the ENSO Tracker is determined by expert analysis from Bureau of Meteorology climatologists and using set criteria. For more details see the 'Criteria' and 'About' tabs.

Recent ENSO values

The graph below shows the fortnightly ENSO status from January 2000 to present.

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Further information

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The status of the ENSO Tracker is determined by expert analysis from climatologists and using the criteria set out below.

El Niño

El Niño WATCH El Niño WATCH

All of the following criteria need to be satisfied:

  1. Current climate state: ENSO phase is currently neutral or declining La Niña.
    • Either:
      SOI analogues: Of the 10 years that most closely resemble the current SOI pattern, 4 or more have shown El Niño characteristics.
    • Or:
      Sub-surface: Significant sub-surface warming has been observed in the western or central equatorial Pacific Ocean.
  2. Models: One-third or more of surveyed climate models show warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific Ocean by late winter or spring.

The chance that an El Niño will occur (based on historical data) is at least 50%.

El Niño ALERT El Niño ALERT

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: A clear warming trend has been observed in the NINO3 or NINO3.4 regions of the Pacific Ocean during the past three to six months.
  2. Winds: Trade winds have been weaker than average in the western or central equatorial Pacific Ocean during any two of the last three months.
  3. SOI: The two-month average SOI is –7 or lower.
  4. Models: A majority of surveyed climate models show warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific Ocean by the late winter or spring.

The chance that an El Niño will occur (based on historical data) is at least 70%.

El Niño EL NIÑO

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: Temperatures in the NINO3 or NINO3.4 regions of the Pacific Ocean are 0.8 °C warmer than average.
  2. Winds: Trade winds have been weaker than average in the western or central equatorial Pacific Ocean during any three of the last four months.
  3. SOI: The three-month average SOI is –7 or lower.
  4. Models: A majority of surveyed climate models show warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific until the end of the year.

Valid until the El Niño is officially declared over by the Bureau of Meteorology.

La Niña

La Niña WATCH La Niña WATCH

All the following criteria need to be satisfied:

  1. Current climate state: ENSO phase is currently neutral or declining El Niño.
    • Either:
      SOI analogues: Of the 10 years that most closely resemble the current SOI pattern, 4 or more have shown La Niña characteristics.
    • Or:
      Sub-surface: Significant sub-surface cooling has been observed in the western or central equatorial Pacific Ocean.
  2. Models: One-third or more of surveyed climate models show cooling to at least 0.8 °C below average in the NINO3 or NINO3.4 regions of the Pacific Ocean by late winter or spring.

The chance that a La Niña will occur (based on historical data) is at least 50%.

La Niña ALERT La Niña ALERT

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: A clear cooling trend has been observed in the NINO3 or NINO3.4 regions of the Pacific Ocean during the past three to six months.
  2. Winds: Trade winds have been stronger than average in the western or central equatorial Pacific Ocean during any two of the last three months.
  3. SOI: The two-month average SOI is +7 or higher.
  4. Models: A majority of surveyed climate models show cooling to at least 0.8 °C below average in the NINO3 or NINO3.4 regions of the Pacific Ocean by the late winter or spring.

The chance that a La Niña will occur (based on historical data) is about 70%.

La Niña LA NIÑA

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: Temperatures in the NINO3 or NINO3.4 regions of the Pacific Ocean are 0.8 °C cooler than average.
  2. Winds: Trade winds have been stronger than average in the western or central equatorial Pacific Ocean during any three of the last four months.
  3. SOI: The three-month average SOI is +7 or higher.
  4. Models: A majority of surveyed climate models show cooling to at least 0.8 °C below average in the NINO3 or NINO3.4 regions of the Pacific Ocean until the end of the year.

Valid until the La Niña is officially declared over by the Bureau of Meteorology.

Neutral

El Niño and La Niña Neutral NEUTRAL

An ENSO event is not active in the tropical Pacific Ocean and there are no signs of an El Niño or La Niña developing.

History of the ENSO Tracker

The below table summarises the ENSO Tracker status by month from 1980 to present.

ENSO status legend

ENW El Niño WATCH
LNA El Niño ALERT
EN EL NIÑO
 
LNW La Niña WATCH
ENA La Niña ALERT
LN LA NIÑA
N NEUTRAL

El Niño and La Niña years

Shading of text in the year column refers to years in which El Niño (red) or La Niña (blue) events began.

Historical values of the ENSO Tracker status prior to 2014 are based on the set criteria alone. Values from the beginning of 2014 include expert analysis by climatologists at the Bureau of Meteorology to make the final assessment on a status level having been reached.