Reports
ENSO Outlook: September 2024
Issued: 7 Oct 2024
This page considers the ENSO outlook for the next three to six months, and the typical impact of El Niño and La Niña events on rainfall in Southeast Asia.
Current SST conditions are shown on the climate monitoring node website: sst - SEA Climate Monitoring
Latest Climate Outlook (June – November 2024): La Niña is likely to develop sometime during JJA 2024, with global climate models predict La Niña conditions to continue until the end of the year
Updated: May 2024
Recent analysis of sea surface temperature (SST) anomalies over the equatorial Pacific shows average to slightly below-average SSTs across the equatorial Pacific Ocean, and along with atmospheric indicators such as trade wind strength and cloudiness, indicate ENSO-neutral conditions. In the Indian Ocean, the Indian Ocean Dipole is also neutral.
The international climate outlook predicts that a La Niña is likely to develop sometime during JJA 2024. After JJA 2024, most models predict La Niña conditions to continue until the end of the year.
The full ASEANCOF-22 Outlook Bulletin (JJA 2024) can be found in the Consensus Bulletin for June-July-August (JJA) 2024 Season document.
Latest Model Outlook
Model outlooks from Copernicus C3S (Figure 1), based on the Nino3.4 SST index, show that now most models predict La Niña conditions between October 2024 to until at least January 2025. However, the models still predict a small chance of ENSO neutral conditions to persist, or the La Niña-like conditions to be short-lived (i.e. not last five consecutive months to declare a La Niña event). Most models are also predicting a weak to moderate strength event.
Impact of El Niño/La Niña on Southeast Asia
The typical impact of El Niño on Southeast Asia is drier-than-average rainfall conditions, including for much of the Maritime Continent during December to February (Figure 2, left). Warmer temperature conditions typically follow drier periods.
The opposite conditions for rainfall (and consequently temperature) are observed during La Niña years (Figure 2, right).
The impact on the region’s rainfall and temperature from ENSO events is more significantly felt during strong
or moderate-intensity events. Also, no two El Niño events or two La Niña events are exactly alike in terms of their impact on the region.
Figure 2: December to February (DJF) season rainfall anomaly composites (mm/day) for El Niño (left) and La Niña (right) years. Brown (green) shades show regions of drier (wetter) conditions. Note that this anomaly composite was generated using a limited number of El Niño and La Niña occurrences between 1979 and 2021 and therefore should be interpreted with caution (data: The Global Precipitation Climatology Project (GPCP) Monthly Analysis Version 2.3).
The typical impact of El Niño on Southeast Asia is drier-than-average rainfall conditions, including during March to May (Figure 2, left). Warmer temperature conditions typically follow drier periods. The opposite conditions for rainfall (and consequently
temperature) are observed during La Niña years (Figure 2, right).
The impact on the region’s rainfall and temperature from ENSO events is more significantly felt during strong or moderate-intensity events. Also, no two El Niño
events or two La Niña events are exactly alike in terms of their impact on the region. 
Figure 2: March to May (MAM) season rainfall anomaly composites (mm/day) for El Niño (left) and La Niña (right) years. Brown (green) shades show regions of drier (wetter) conditions. Note that this anomaly composite was generated using a limited number of El Niño and La Niña occurrences between 1979 and 2021 and therefore should be interpreted with caution (data: The Global Precipitation Climatology Project (GPCP) Monthly Analysis Version 2.3).
The typical impact of El Niño on Southeast Asia is drier-than-average rainfall conditions, including for much of the Maritime Continent during June to August (Figure 2, left). Warmer temperature conditions typically follow drier periods. The opposite
conditions for rainfall (and consequently temperature) are observed during La Niña years (Figure 2, right).
The impact on the region’s rainfall and temperature from ENSO events is more significantly felt during strong or moderate-intensity events. Also, no two El Niño events or two La Niña events are exactly alike in terms of their
impact on the region.
Figure 2: June to August (JJA) season rainfall anomaly composites (mm/day) for El Niño (left) and La Niña (right) years. Brown (green) shades show regions of drier (wetter) conditions. Note that this anomaly composite was generated using a limited number of El Niño and La Niña occurrences between 1979 and 2021 and therefore should be interpreted with caution (data: The Global Precipitation Climatology Project (GPCP) Monthly Analysis Version 2.3).
The typical impact of El Niño on Southeast Asia is drier-than-average rainfall conditions, including for much of the Maritime Continent during September to November (Figure 2, left). Warmer temperature conditions typically follow drier periods.
The opposite conditions for rainfall (and consequently temperature) are observed during La Niña years (Figure 2, right).
The impact on the region’s rainfall and temperature from ENSO events is more significantly felt during strong or moderate-intensity events. Also, no two El Niño events or two La Niña events are exactly alike in terms of their
impact on the region. 
Figure 2: September to November (SON) season rainfall anomaly composites (mm/day) for El Niño (left) and La Niña (right) years. Brown (green) shades show regions of drier (wetter) conditions. Note that this anomaly composite was generated using a limited number of El Niño and La Niña occurrences between 1979 and 2021 and therefore should be interpreted with caution (data: The Global Precipitation Climatology Project (GPCP) Monthly Analysis Version 2.3).