APEC Climate Centre Issues El Nino Watch: Concerns Over South-West Monsoon 2026 Outlook
The APEC Climate Centre (APCC), the apex climate prediction body for the Asia-Pacific region, has issued an El Nino watch, warning that drought-bearing El Nino conditions are likely to emerge by July 2026
Above-normal temperatures are predicted across India over the next six months, with below-normal rainfall expected during the monsoon season
The current La Nina phase is transitioning to ENSO-neutral in early 2026, with most climate models predicting El Nino development in the second half of the year
The El Nino is expected to strengthen during the middle of the Indian monsoon season (July-September) and peak during the Northern Hemisphere winter, raising concerns about drought conditions and agricultural output
El Nino-Southern Oscillation (ENSO): Mechanism and Phases
ENSO is a coupled ocean-atmosphere climate phenomenon in the tropical Pacific Ocean that has global impacts on weather patterns. It consists of two opposing phases — El Nino (warm phase) and La Nina (cool phase) — and a neutral phase. El Nino occurs when sea surface temperatures (SSTs) in the central and eastern equatorial Pacific Ocean become anomalously warm (above +0.5 degrees Celsius), weakening the trade winds and disrupting the Walker Circulation.
The APCC's El Nino watch signals a transition from ENSO-neutral to El Nino phase during the critical monsoon months, which would weaken the Walker Circulation and suppress convective activity over the Indian subcontinent.
El Nino and Indian Summer Monsoon: Historical Relationship
The Indian Summer Monsoon (ISM), active from June to September, provides approximately 70-75% of India's annual rainfall and is critical for kharif agriculture. El Nino events have historically been associated with below-normal monsoon rainfall in India. The mechanism involves El Nino-induced subsidence (sinking air) over the Indian region, which weakens the monsoon circulation.
Key Details
- Of the 15 major droughts in India between 1950 and 2023, over 60% coincided with El Nino years
- Notable El Nino drought years: 1965, 1972, 1982, 1987, 2002, 2009, 2015 (though 2015 was partially offset by positive IOD)
- Not all El Nino years produce droughts — the relationship is probabilistic, not deterministic (e.g., 1997 had strong El Nino but near-normal monsoon)
- Indian Meteorological Department (IMD) defines "normal" monsoon as rainfall within the range of 96-104% of the Long Period Average (LPA = 87 cm, 1971-2020 baseline)
- Monsoon deficit: Below 90% of LPA is classified as a "drought year" by IMD
- India's kharif crops (rice, pulses, cotton, sugarcane) are directly dependent on monsoon rainfall — a deficit monsoon impacts food production, inflation, and rural employment
If El Nino materialises by July 2026 as APCC predicts, it would coincide with the peak monsoon months (July-August), potentially suppressing rainfall during the most critical period for kharif sowing and crop development.
Indian Ocean Dipole (IOD): The Counterbalancing Factor
The Indian Ocean Dipole is an independent ocean-atmosphere phenomenon characterised by the difference in sea surface temperatures between the western and eastern Indian Ocean. A positive IOD (warmer western Indian Ocean, cooler eastern Indian Ocean) can partially or fully counteract the negative impact of El Nino on the Indian monsoon by enhancing moisture supply and convective activity over the Indian subcontinent.
Whether the 2026 monsoon will be severely impacted depends not only on El Nino's intensity but also on the IOD phase — a concurrent positive IOD could partially offset El Nino's negative impact, while a negative or neutral IOD would amplify drought risk.
India Meteorological Department (IMD): Monsoon Forecasting Framework
IMD is India's principal weather forecasting agency, established in 1875 and currently functioning under the Ministry of Earth Sciences. IMD issues two-stage operational monsoon forecasts: the first in April (long-range forecast using statistical and dynamical models) and the second in June (updated forecast). These forecasts are critical for agricultural planning, water resource management, and economic policy.
IMD's first operational monsoon forecast (due April 2026) will be the first authoritative assessment of whether El Nino's impact on the 2026 monsoon will be significant enough to warrant drought preparedness measures.
- APCC El Nino watch: El Nino conditions likely to emerge by July 2026
- Current ENSO phase: La Nina transitioning to ENSO-neutral in early 2026
- El Nino threshold: SST anomaly above +0.5 degrees Celsius in Nino 3.4 region for 5 overlapping 3-month periods
- Indian monsoon contributes: 70-75% of India's annual rainfall (June-September)
- LPA (Long Period Average): 87 cm (1971-2020 baseline)
- Normal monsoon range: 96-104% of LPA; drought threshold: below 90% of LPA
- Over 60% of major Indian droughts (1950-2023) coincided with El Nino years
- Rain-fed agriculture: ~52% of India's net sown area (~140 million hectares total)
- IMD first monsoon forecast: Expected April 2026
- IOD: Can counterbalance El Nino's negative impact on Indian monsoon (e.g., 2019 — positive IOD + El Nino Modoki = above-normal rainfall)