Very Strong El Nino: Raises Risk Of Extreme Weather Across The Globe

Key Takeaways:

• The exceptionally strong El Niño event is projected to persist through February 2027, with Niño 3.4 reaching 2.3°C.
• Subsurface Pacific Ocean temperature anomalies exceeding 8°C indicate significant strengthening of El Niño.
• The Indian Ocean Dipole remains positive at +0.6°C and could support rainfall during the upcoming Northeast Monsoon season.
• The MJO may become favourable for cyclone activity over the Indian seas in late October, although no cyclone is predicted before the last week.
• Forecast Validity: Until next update.

The timelines of a very strong El Niño are getting stretched further. As per the Climate Prediction Center, there is a 100% likelihood that the exceptionally strong El Niño event will persist through February 2027. The World Meteorological Organization does confirm that the event is steadily intensifying and is projected to peak as one of the strongest El Niño episodes on record during the Northern Hemisphere fall and winter season of 2026–27. But El Niño cannot be read in isolation, and a very strong El Niño does not mean the same impact everywhere. Its effects vary according to location and season and are subject to modification by other climate drivers, including conditions in the Indian and Atlantic Oceans.

A positive phase of the IOD is evolving in the Indian Ocean and is expected to strengthen during the October–November–December quarter. Meanwhile, the equatorial Atlantic basin is forecast to remain generally warm, with SSTs in both the North and South Tropical Atlantic staying well above normal. These conditions may reinforce, weaken or alter typical El Niño impacts in different regions.

ENSO: The 2026 El Niño event continues to intensify across the central and eastern Equatorial Pacific. The traditional Niño 3.4 index shows a pronounced and sustained rise. Oceanic and atmospheric indicators are increasingly aligned, providing strong evidence of extraordinary intensification. The latest weekly Niño 3.4 index, centred on 5th October 2026, climbed to 2.3°C, the highest so far. In addition, the equatorial Southern Oscillation Index (SOI) has risen to -2°C.

The persistently negative SOI values indicate a pronounced weakening of the Walker Circulation, consistent with the ongoing growth of El Niño. Further proof of El Niño strengthening comes from the explosive subsurface warming across the central and eastern Equatorial Pacific. The subsurface warming at approximately 50–150 metres in the Niño region, between 160°E and 80°W, is exceeding climatological averages by more than 8°C, more so in the Niño 3.4 region. The exceptionally high heat content at and below the ocean surface, acting in tandem with the favourable pressure field, will further strengthen the ocean-atmosphere coupling.

The Niño indices are behaving more or less like a ‘canonical’ El Niño, wherein the extreme western parts of the Niño region, hosting Niño 4, are the coolest of all, and Niño 1+2 is the hottest one. Niño 4 has had a temperature anomaly of ±0.1°C for the last eight weeks, and Niño 1+2 has now warmed up to 4.5°C. During the 2023 El Niño, this index had touched a high of 3.5°C in July 2023. Even the Niño 3 region has had an anomaly in excess of 3°C for the last three weeks. All these indicate a rare occurrence of an extremely strong El Niño coming up during the next quarter, October–November–December.

IOD: The Indian Ocean Dipole continues to exceed the positive threshold of +0.4°C for the fourth consecutive week. The latest index value for the week ending 4th October 2026 was +0.6°C, a marginal drop from the previous two weeks. Sustained values above the threshold are required before an event is considered established. As per model guidance, a positive IOD is likely to develop, albeit with uncertainty about the strength and duration of the event.

MJO: El Niño continues to dominate the global tropics. The MJO remains suppressed and difficult to discern. But there are indications that the MJO pulse is likely to propagate to the Indian Ocean with increasing amplitude during the second half of October. The current position of the MJO between phases 7, 8 and 1 favours storm activity in the Western and Eastern Pacific Oceans. The second half of October may find support from the MJO for cyclone activity over the Indian seas.

A growing positive IOD is a good sign for the upcoming Northeast Monsoon season. While the peninsula and southern regions benefit from enhanced moisture through positive IOD conditions, Northeast India often records suppressed or below-normal rainfall. It is a bit early to predict any cyclone in the Indian seas, and if at all, it will not be earlier than the last week of October.