ENSO
ENSO Outlook: May 2026
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 2026): A moderate El Niño is likely to develop during JJA 2026, global climate models predict possible continued strengthening into a strong to very strong El Niño after JJA 2026
Updated: May 2026
Recent sea surface temperature anomalies over the equatorial Pacific Ocean during April-May 2026 overall indicated ENSO neutral conditions were present. However, persistent warming over most of the Niño regions, together with atmospheric indicators such as decreased cloudiness over most parts of Southeast Asia and anomalous low-level westerlies east of the Philippines, support the development of El Niño-like conditions. Meanwhile, the Indian Ocean remains in a neutral Indian Ocean Dipole (IOD) phase.
International climate outlooks predict a moderate El Niño is likely to develop during June to August (JJA) 2026. After JJA, most models predict continued strengthening into a strong to very strong El Niño, while the rest predict only moderate El Niño conditions to persist through the remainder of the year. If a very strong El Niño occurs, this does not necessarily indicate bigger impacts on Southeast Asia’s climate but rather that typical impacts from El Niño events are more likely to occur. The IOD is also predicted to transition to positive IOD conditions through the latter part of 2026, although with less confidence than the predicted El Niño.
Latest Model Outlook
Model outlooks from Copernicus C3S (Figure 1), based on the Relative Nino3.4 SST index, predict the index to continue warming, with a transition to El Niño conditions very likely during June-July 2026. The El Niño conditions are predicted to persist at least until October 2026, with most models predicting the strength of the El Niño conditions to be moderate or strong. However, there is still uncertainty in the long-term forecasts at this time of the year, therefore the strength of the predicted El Niño conditions is uncertain.
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).