EI Niño/La Niña Status

Updated on 19 June 2026

The El Niño – Southern Oscillation (ENSO) monitoring system state is “El Niño Conditions”. The Nino3.4 index now supports the presence of El Nino conditions. Key atmospheric indicators (cloudiness and trade wind anomalies) also support the presence of El Nino conditions.
The Nino3.4 index was 0.5°C for May 2026, with further warming in the first half of June, and 0.0°C for the three-month average March – May 2026 based on the Relative Oceanic Nino Index.

Models strongly agree that the El Niño conditions will continue through the second half of 2026, with strong conditions likely from August-September 2026.

Short note on the Indian Ocean Dipole: The Indian Ocean Dipole (IOD) was neutral in May 2026. Models predict a positive IOD to develop in July-August 2026.

Further Information on ENSO

The sea surface temperatures (SSTs) in the tropical Pacific in May 2026 were above-average in the central portion of the region and a mix of below- to above-average in the west (Figure 1). The warm (positive) anomalies developing in the Nino3.4 region (red box), are indicative of transition to El Niño conditions during May, with further warming in June based on a preliminary assessment (not shown). SSTs were near-to above average over eastern equatorial Indian ocean and below-to-near-average over western equatorial Indian ocean, resulting to slightly negative values of IOD index but still within the neutral range.

Figure 1: Relative SST anomalies (to the average tropical SST anomaly) for May 2026 using ERSST v5 data. Red (blue) shades show regions of relative warming (cooling). The tropical Pacific Ocean Nino3.4 Region is outlined in red. The Indian Ocean Dipole index is the difference between average SST anomalies over the western Indian Ocean (black solid box) and the eastern Indian Ocean (black dotted box).

Looking at the Relative Nino3.4 index in Figure 2, the 1-month Relative Nino3.4 index was negative, but within the neutral range, between March 2025 and August 2025. The index passed the La Niña threshold in September 2025 and returned to the neutral range in March 2026. Since March, the index has continued to warm. While the May value was just below the El Niño threshold, further warming in June made the 10 May – 13 June 2026 average above the El Niño threshold (not shown). For El Niño conditions to be present, 1-month warm SST anomalies (observed or forecast) should persist for at least four months above the El Niño threshold, with at least one of the months observed; along with supporting atmospheric observations.

Figure 2: The Relative Nino3.4 index using the 1-month SST anomalies. Warm anomalies (≥ +0.6; brown4) correspond to El Niño conditions while cold anomalies (≤ -0.6; blue) correspond to La Niña conditions; otherwise neutral (> -0.6 and < +0.6; grey).

Model outlooks from Copernicus C3S (Figure 3), based on the Relative Nino3.4 SST index, predict the index to be above the El Niño threshold in June 2026. The El Niño conditions are predicted to continue at least until November 2026. Most models predict the El Niño conditions to be strong from August-September 2026. El Niño conditions typically peak around the end of the year and return to neutral the following year so, although the forecasts in Figure 3 are only to November 2026, the El Niño is very likely to continue beyond this date.

Figure 3: Forecasts of Relative Nino3.4 strength until November 2026 from various seasonal prediction models from international climate centres (grey lines). The solid blue and yellow lines note the La Niña and El Niño thresholds used by MSS.

Historical ENSO Variability
To classify a historical El Niño event, the Relative Oceanic Nino Index (RONI, or 3-month average Relative Nino3.4 value), must be above 0.6°C for 5 or more consecutive months. For La Niña events, the threshold is -0.6°C. Otherwise it is considered neutral. ENSO events with a peak value above 1.5°C (El Niño) or below -1.5°C (La Niña) are considered strong. Otherwise, the events are considered weak to moderate in strength. The following figure (Figure 4) shows the development the Relative Nino3.4 index for recent El Niño and La Niña events in comparison to other El Niño/La Niña events.

Figure 4: Relative Oceanic Nino Index (RONI) development and retreat of different El Niño (left)/La Niña (right) events since the 1960s. Recent El Niño and La Niña events are in red and purple, respectively.

Impact of El Niño/La Niña on Singapore

During the Southwest Monsoon months from June to September the correlation of ENSO with rainfall over Singapore is strong, (Figure 5), i.e. if El Niño or La Niña conditions are present, the rainfall patterns are likely to be influenced, particularly by a moderate or strong event (although there can still be considerable variability at the monthly timescale). When there are no El Niño or La Niña conditions present (i.e. ENSO-neutral), there is a large variability in rainfall (Figure 6).

Figure 5: Correlation between total 3-month seasonal rainfall (averaged over Singapore stations) and seasonal Nino3.4 index from 1991-2025. The statistically significant correlations at the 95% level (±0.34) in grey, and at 99% level (±0.43) in red.

Figure 6: Singapore rainfall anomalies for June –October (as a departure from the 1991-2020 long-term rainfall average) arranged in the order from strong La Niña (left) to strong El Niño (right). Orange bars denote El Niño years’ anomalies, blue bars denote La Niña years’ anomalies, and grey bars denote ENSO neutral years’ anomalies.

References

Turkington, T., Timbal, B., & Rahmat, R. (2018). The impact of global warming on sea surface temperature based El Nino Southern Oscillation monitoring indices. International Journal of Climatology, 39(2).