Climate Driver Update history
Climate drivers in the Pacific, Indian and Southern oceans and the Tropics

In the tropical Pacific Ocean, October sea surface temperatures (SSTs) were:

• up to 1.2 °C warmer than average in the far western tropical and far eastern equatorial Pacific Ocean
• up to 1.2 °C cooler than average in the central and eastern equatorial Pacific, east of 170°W

In Australian coastal waters, October SSTs were:

• up to 2 °C warmer than average in waters surrounding most of Australia, reaching up to 3 °C warmer than average off the north-west and south-east coasts.

Around the Maritime Continent, October SSTs were:

• up to 2 °C warmer than average

The Bureau's long-range forecast for December 2024 to February 2025 indicates SSTs are likely to be:

• up to 1.2 °C warmer than average in the far western Pacific (west of 170°E)
• close to average across most of the equatorial Pacific, east of 170°E with the exception of a small region of the equatorial Pacific between 120°E and 130°E, where it is forecast to be up to 0.8 °C cooler than average
• up to 1.2 °C warmer than average across most of Australia's coastal waters, and reaching up to 2 °C warmer in the north-west and up to 3 °C warmer in the south-east
• up to 1.2 °C warmer than average across the Maritime Continent.

ENSO and the IOD are only broad indicators of the expected climate. The long-range forecast provides better guidance on local rainfall and temperature patterns.

For the week ending 10 November 2024, sea surface temperatures (SSTs) were:

• 0.8–2 °C warmer than the 1991–2020 average in the far western and parts of the central and eastern Pacific north of the equator
• 0.8–2 °C cooler than average in the central and eastern equatorial Pacific, east of the Date Line
• warmer than average across much of the north Pacific, with much of the region surrounding and to the east of Japan more than 3–4 °C warmer than average
• 0.4–2 °C warmer than average around most of Australia's coastline and parts of the Tasman and Coral seas, with areas off the south-east coast up to 3 °C warmer than average
• 0.4–2 °C warmer than average across most of the Maritime Continent.

The Niño indices for the week ending 10 November 2024 were: Niño3, −0.33 °C; Niño3.4, −0.37 °C; and Niño4, +0.10 °C. The Niño3.4 index reflects historically neutral ENSO conditions.

• The SOI values reflect ENSO-neutral conditions.
• The 30–, 60– and 90-day Southern Oscillation Index (SOI) for the period ending 10 November were +1.2, +1.0 and +3.3, respectively.
• Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below −7 typically indicate El Niño. Values between +7 and −7 generally indicate neutral conditions.

• Trade wind strength for the 5 days ending 10 November was slightly stronger than average in the western Pacific and close to average across the central Pacific.
• There is a lack of data in the eastern Pacific, which makes it difficult to identify trade wind anomaly patterns in this region
• Monthly averaged trade winds have been stronger than average across the equatorial Pacific since July.
• During La Niña events, there is typically a sustained strengthening of trade winds across much of the tropical Pacific, while during El Niño there is a sustained weakening, or even reversal, of trade winds.

• A strong Madden–Julian Oscillation (MJO) pulse is currently located in the Western Hemisphere (as at 8 November).
• Most models suggest the MJO will become indiscernible, but some maintain a weak to moderate MJO pulse as it moves over the Indian Ocean in the coming fortnight.

Current state

• The Indian Ocean Dipole (IOD) is neutral. The IOD index for the week ending 10 November was −0.69 °C, making it the fifth consecutive week below the negative IOD threshold (–0.4 °C).
• Sea surface temperatures (SSTs) for the week ending 10 November 2024 were 0.8–2 °C warmer than the 1991–2020 average across much of the central and eastern Indian Ocean and close to average in the western equatorial Indian Ocean (with a small part of this area being up to -0.8 °C cooler than average). This pattern is typical of the ocean pattern associated with a negative IOD phase.
• Closer to Australia, SSTs were up to 3 °C warmer than average for waters surrounding northern WA.

Forecast

• All surveyed climate models indicate that the IOD index will meet or exceed negative IOD thresholds in November, with all but one returning to neutral levels in December.
• To be classified as a negative IOD event, the index needs to be at values below the negative IOD threshold for sustained period of at least 6 to 8 weeks.
• IOD forecast skill has historically been moderate for forecasts out to 1 month ahead.

• Cloudiness near the equatorial International Date Line is currently below average as at 10 November
• Cloudiness has been below average since early September.
• Prior to September, cloudiness fluctuated around average for most of the year.
• Equatorial cloudiness near the International Date Line typically increases during El Niño (below average outgoing longwave radiation - OLR) and decreases during La Niña (above average OLR).

The equatorial Pacific sub-surface temperature anomalies for the 30 days ending 4 November 2024 show:

• cooler than average waters in the eastern half of the equatorial Pacific down to about 175 m depth; cooler waters peak around 50 to 100 m depth in the eastern Pacific where they are more than 4 °C cooler than average.
• warmer than average waters in the western half of the equatorial Pacific down to about 300 m depth in the far western Pacific. Waters are 2 to 4 °C warmer than average in the far western Pacific between 75 m and 150 m depth.

For the 5 days ending 11 November 2024, the analysis shows:

• sub-surface temperatures up to 2 °C cooler than average in areas of the central equatorial Pacific (between 100 m and 175 m depth) and eastern equatorial Pacific (between 50 m to 100 m depth).
• sub-surface temperatures up to 3 °C warmer than average in the western equatorial sub-surface (between 100 m and 150 m depth) and in the eastern equatorial sub-surface (above 50 m depth).

The El Niño–Southern Oscillation (ENSO) remains neutral, with sea surface temperatures (SSTs) in the central equatorial Pacific Ocean at ENSO-neutral levels. Atmospheric indices, such as those related to patterns of surface pressure, cloud and trade winds, are broadly consistent with an ENSO-neutral state. While some have displayed La Niña-like signals over recent months, a consistent and sustained shift in the atmosphere has not been observed.

The Bureau's model suggests SSTs are likely to remain within the ENSO-neutral thresholds (−0.8 °C to +0.8 °C) throughout the forecast period to February 2025. Of the 6 other climate models surveyed, only one model suggests SSTs in the tropical Pacific are likely to exceed the La Niña threshold (below −0.8 °C) throughout December to February, which is sufficient time to be classified as a La Niña event. All models forecast neutral ENSO values by March.

The latest Indian Ocean Dipole (IOD) index value is −0.69 °C for the week ending 10 November, marking the fifth week below the negative IOD threshold (−0.40 °C). All models indicate that the IOD index will meet or exceed negative IOD thresholds in November, with all but one returning to neutral levels in December.

Global SSTs remain at near record levels as at 31 October, with temperatures since July being just short of the record temperatures observed during 2023, yet above all other years since observations began in 1854. The sustained nature of this significant global ocean heat suggests that climate indicators such as ENSO and IOD may not behave or evolve as they have in the past.

The Southern Annular Mode (SAM) index is positive as at 10 November and is forecast to remain mostly positive over the second half of November. SAM is also forecast to have a greater than usual chance of being in the positive phase during December.

The Madden–Julian Oscillation (MJO) is in the Western Hemisphere as at 10 November. Climate models indicate the MJO will continue to move eastwards towards the Indian Ocean over the coming week. Models show a spread on the likely strength, with most suggesting the MJO will become indiscernible, but some maintaining a weak to moderate MJO pulse as it moves over the Indian Ocean in the coming fortnight.

ENSO, IOD, MJO and SAM are broad indicators of the expected climate and are just some of many factors in a complex system. The long-range forecast provides better guidance on local rainfall and temperature patterns.

• The Southern Annular Mode (SAM) is positive (as at 8 November) and forecast to remain mostly positive in the coming fortnight.
• Predictability of the SAM beyond two weeks is typically low but at this time of the year, there is some predictability up to 2 months ahead.
• SAM is forecast to have a greater than usual chance of being in the positive phase during December.

• ENSO is currently neutral.
• The Bureau's model suggests SSTs are likely to remain within the ENSO-neutral range (−0.8 °C to +0.8 °C) throughout the forecast period.

• Of the 6 climate models surveyed (in addition to the Bureau model), only one suggests SSTs in the tropical Pacific are likely to meet or exceed the La Niña threshold (below −0.8 °C) throughout December to February, which would be a sufficient length of time to be classified as a La Niña event.

• Should a La Niña develop, it is forecast to be relatively weak (in terms of the magnitude of the SST anomaly) and short-lived, with all models forecasting ENSO-neutral by March 2025.
• In order for observed conditions to lead to the declaration of a La Niña event, both cool SSTs in the tropical Pacific and corresponding atmospheric indicators, must be sustained for at least 2 to 3 months.
• At this time of year, ENSO forecast skill is high for up to 4 months ahead.