Indian Ocean dipole latest update
DWM IOD MONITORING UPDATE
17 August 2026 | 09:00 AM IST
\#Topic : Indian Ocean still struggling to establish a Positive IOD development.
==> Severe Super El Nino conditions continue to gradually develop across the Pacific Ocean and are expected to peak in November.
==> Meanwhile, the Indian Ocean is attempting a transition toward Positive Indian Ocean Dipole (pIOD) conditions. Over the past three weeks, weekly IOD values stood at +0.44 °C, +0.63 °C and +0.41 °C.
==> After three consecutive positive weeks, the latest value has dropped to +0.18 °C, showing a clear weakening trend over the last two weeks.
==> Strong westerly wind bursts and planetary wave activity have disrupted the development of the positive IOD. However, emerging wind suppression is expected to support renewed strengthening in the coming weeks.
==> As discussed earlier, the PIOD is likely to reach its peak only in November, giving us sufficient time for proper development.
==> Positive IOD events normally build gradually during the southwest monsoon and peak between September and November. This year’s evolution has been delayed and is currently facing another disturbances.
==> If IOD values remain at or above +0.4°© continuously for the next eight weeks, a positive IOD event is likely to become establish by late October.
==> In Super El Nino years, the PIOD peak has historically occurred in November. For reference:
1972: +0.91 °C
1982: +0.87 °C
1997: +1.55 °C
2023: +1.50 °C
(2015 was an exception — it peaked at +0.71 °C in September and then weakened through the northeast monsoon season.)
Note: The strongest positive IOD on record was +1.8 °C in November 2019, but that year was not an El Niño year and is therefore excluded from this comparison.
==> Current numerical models may be underestimating the potential intensity of the developing PIOD. There remains a realistic possibility of strong positive IOD conditions exceeding +1.5 °C by early November.
==> In the coming weeks, IOD values are expected to turn firmly positive again. Eight consecutive weeks of positive values will be required before a positive IOD event can be officially declared.
==> Once established, the positive IOD is likely to exert a significant influence on the northeast monsoon. It will have no impact on the ongoing southwest monsoon.
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