Explain why the 1997 El Niño did not cause a drought in India while the 2026 monsoon was deficient. What are the lessons for seasonal forecasting?

India's southwest monsoon depends on more than one ocean, not on the Pacific alone. Since 1950, seven monsoons have coincided with a moderate or strong El Niño, and five of them were deficient [6]. 1997 escaped, while 2026 fell about 13% short [6]. What decided the outcome was what accompanied El Niño.

Why 1997 escaped drought

• Strong El Niño, normal rain: some feared an extreme deficit based on El Niño alone. Instead, June–September rainfall was 2% above normal [2].
• Positive Indian Ocean Dipole (IOD): a warmer western Indian Ocean strengthened the monsoon during the season [3]. A positive IOD can offset El Niño's suppressing effect [1].

Why 2026 was deficient

• No timely counterweight: the IOD was expected to stay neutral and turn positive only near the end of the season [4]. That was too late to make up for rain lost in June–August.
• El Niño unchecked: El Niño developed during the season and is expected to peak only in December [6].
• Outcome: rainfall was about 13% below the 87 cm long-term average. East and Northeast India had their driest monsoon since 1901 [6].

1997: El Niño + in-season positive IOD → offset    → +2% (normal)
2026: El Niño + neutral IOD (late +ve) → no offset → ~−13% (deficient)

Fig: Same driver, different outcomes

Lessons for seasonal forecasting

• Use several ocean basins: track ENSO and the IOD together. IMD now combines dynamical models such as the Monsoon Mission's MMCFS with statistical models [4].
• Timing matters, not just sign: IOD outlooks must say when a positive phase is expected.
• Probabilities over single numbers: IMD's 2026 forecasts (92%, then 90% of the Long Period Average) got the direction right. The chance of a deficient season rose from 35% to 60% [4][5], a clearer warning than any single figure.
• Regional detail: the national average hid record deficits in the East and Northeast [6]. Contingency crop plans need forecasts at the subdivision level.
• Look beyond September: with El Niño peaking in December [6], extended-range outlooks are needed to plan the rabi season and manage reservoirs.

1997 and 2026 show that El Niño is a strong risk factor, but it does not decide the outcome on its own. The interplay of Pacific and Indian Ocean signals, and their timing, does. Forecasts that are probabilistic, cover several ocean basins and give regional detail can turn better forecasting into resilience for farmers when linked to early drought preparedness. That advances SDG 2 (Zero Hunger) and SDG 13 (Climate Action).