Climate Model Summary

Australian climate is influenced by sea surface temperature patterns in the Pacific and Indian oceans. This page provides information on Pacific and Indian ocean outlooks for the coming six months based on a survey of international climate models.

These charts are also available in the Climate Driver Update, along with written details, more charts, and information about other climate drivers.

Further details: Climate Driver Update . Climate Outlooks

Average of international model outlooks for NINO3.4

Average of international model outlooks for the Indian Ocean Dipole (IOD)

Based on the ensemble mean for the most recent model run.

The arrows on the dials indicate the combined average of monthly outlooks from a survey of international global climate models. Note that the individual model runs vary around the average.

 

NINO3.4 covers the central Pacific region.

Graphs

Nino 3.4 2 month outlook Models information
Graph details

The graphs are based on the ensemble mean for the most recent model run.

These graphs show the average forecast value of NINO3.4 for each international model surveyed for the selected calendar month. If the bars on the graph are approaching or exceeding the blue dashed line, there is an increased risk of La Niña. Similarly, if the bars on the graph are approaching or exceeding the red dashed line, there is an increased chance of El Niño.


Graphs

Latest IOD outlook Models information
Graph details

The graphs are based on the ensemble mean for the most recent model run.

Thse graphs show the average forecast value of the IOD index for each international model surveyed for the selected calendar month. If the majority of models are approaching or exceeding the blue dashed line, then there is an increased risk of a negative IOD event. If the majority of models are approaching or exceeding the red dashed line, then there is an increased risk of a positive IOD event.


More information:

Sea surface temperature graphs

Australian climate is influenced by sea surface temperature patterns in the Pacific and Indian oceans. Specific regions are monitored, as they can indicate the presence, or potential development, of ENSO (El Niño/La Niña) and Indian Ocean Dipole (IOD) events.

Sea surface temperature graphs

NINO34 predictions for the next 5 months.

Long-range forecast graph for selected SST region

NINO34 probabilities

Product code: IDCK000073

Model details

The models used within our survey are listed below with links to their agency homepages, model output and technical information about the model.

Model data are provided for Bureau of Meteorology use by the agencies detailed in the Models section. Respective agency copyright applies to these data.

Models indicate La Niña to ease in early 2023

La Niña continues in the tropical Pacific but has weakened from its peak, and recent observations and model outlooks indicate this event is easing. All models indicate a return to neutral NINO3.4 index values during February 2023. La Niña typically increases the chance of above average summer rainfall in eastern and northern Australia. 

The Indian Ocean Dipole (IOD) is neutral. The IOD has little influence on Australian climate while the monsoon trough is in the southern hemisphere (typically December to April).

NINO3.4 outlook

La Niña remains active, but is likely past its peak. Recent observations and model outlooks indicate this event is easing. The Bureau's latest weekly NINO3.4 value to 15 January 2023 was −0.6 °C, which is outside La Niña thresholds (−0.8 °C and cooler).   

All surveyed climate models indicate sea surface temperatures in the central tropical Pacific (NINO3.4) will return to ENSO-neutral by February 2023 and remain at neutral levels until at least the end of the southern hemisphere autumn. Model accuracy is generally lower at this time of year than at other times, therefore, outlooks through and beyond autumn should be viewed with caution. 

ENSO events typically peak in late (southern hemisphere) summer and decay during the autumn; the current outlooks indicate this La Niña event will decay slightly earlier than usual. La Niña events typically increase the chance of above-average rainfall for northern and eastern Australia during summer. When ENSO is neutral, there is typically little influence on Australian climate patterns from the Pacific Ocean. 

Persistent NINO3.4 values above +0.8 °C typically indicate El Niño, while values below −0.8 °C typically indicate La Niña.

 

 

Indian Ocean Dipole (IOD) outlook

The IOD is neutral. The latest IOD index value for the week ending 15 January 2023 was +0.0 °C. All models indicate the IOD will remain neutral for next three months, February to April. 

IOD events are typically unable to form between December and April, while the monsoon trough is in the southern hemisphere. This is due to the monsoon trough's influence on local wind patterns. As a result, the IOD has little effect on Australian climate at this time of year. 

A couple of models indicate the possibility of a positive IOD event in early winter. A positive IOD often results in less winter and spring rainfall across much of Australia. Model accuracy is generally lower at this time of year than at other times, therefore, outlooks through and beyond autumn should be viewed with caution.

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Australian Community Climate Earth-System Simulator–Seasonal (ACCESS–S)

The Bureau of Meteorology's climate model generates a six-month forecast for NINO and IOD indices each fortnight. 

The latest model run (generated 14 January 2023) indicates sea surface temperatures in the central tropical Pacific (NINO3.4) are likely to continue to warm during February and throughout the outlook period but remain in the neutral range until at least May. Model accuracy is generally lower at this time of year than at other times, therefore, outlooks through and beyond autumn should be viewed with caution. 

For the Indian Ocean Dipole (IOD), the Bureau's model indicates IOD index values are likely to remain neutral throughout the outlook period. Model accuracy is generally lower at this time of year than at other times, therefore, outlooks through and beyond autumn should be viewed with caution. The IOD typically has little impact on Australian climate from December to April, while the monsoon trough is in the southern hemisphere. The forecast values, shown below in bold, are for the model's ensemble mean. 

Product code: IDCKGL0000

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