El Nino Strikes Indian Monsoon: Triggers Drought After A Decade

Key Takeaways:

• Indian monsoon 2026 suffered a 13% rainfall shortfall, resulting in a mild meteorological drought.
• Since 2001, India has experienced six monsoon droughts, five of which were associated with El Niño.
• El Niño 2026 continues to strengthen, with exceptionally high temperature anomalies over the equatorial Pacific.
• Positive IOD conditions are strengthening, while the MJO is unlikely to favour tropical storm activity over Indian seas in the first half of October.
• Forecast Validity: Till Next Update

The ‘super’ El Niño has struck the Indian monsoon, triggering a drought after a decade of decent seasons. Mercifully, it was contained within the ‘mild’ category of ‘Meteorological Drought’, with a shortfall of 13% rainfall across the country. It largely spared the eastern and central parts of the country from its adverse impact. However, it did punish severely some pockets in the north and south alike.

Since 2001, the Indian monsoon has suffered six droughts, including the current one of 2026. Five of these were El Niño-triggered, including the two severe droughts in 2002 and 2009.

ENSO: El Niño 2026 appears to be the strongest, at least since reliable records started being maintained. Ocean surface temperatures have already surpassed a three-decade average, and the peak is yet to come. The sub-surface temperatures have become warmer by 7°-8°C than normal. The ongoing strengthening of the event indicates that the worst is yet to arrive.

The latest data shows that the sea surface temperature at the centre of the Niño region in the equatorial Pacific has reached 3.05°C, overtaking the previous high of 3.02°C set during the last super El Niño of 2015, in November 2015. The highest value of the Niño 3.4 index during the last El Niño of 2023 was 2.1°C in November 2023.

All four Niño indices have either retained or marginally increased the temperature anomaly. The eastern half of the equatorial Pacific is much warmer than the western and central regions. The negative value of the temperature anomaly in Niño 4 makes the event identical to a ‘Canonic’ El Niño.

IOD: There has been a steady rise in the Indian Ocean Dipole index over the last seven weeks. It has maintained a positive value above the threshold mark of +0.4°C for the last three weeks. The latest index value for the week ending 27 September 2026 was +0.76°C. This is the highest value since March 2026.

The positive IOD is likely to develop during the autumn of the Northern Hemisphere and persist through the fall of the year and early winter of 2027. Uncertainty still remains about its peak and duration.

MJO: The Madden-Julian Oscillation activity remains difficult to discern within the background of strong and persistent El Niño conditions in the equatorial Pacific. The pulse is likely to remain over the Western Hemisphere and Africa in Phases 1 and 8 until mid-October. This position will not favour any tropical storm activity in the Indian seas during the first half of October.

Both ocean and atmospheric indices reflect values consistent with a very strong El Niño, with further intensification during the forecast period of the next quarter. However, a strong El Niño signal in the Niño 3.4 region does not necessarily mean a proportionately strong impact on rainfall and temperatures over the Indian subcontinent.