NOAA declared El Niño officially formed in June 2026. Thailand's central-region reservoirs are already below the 30% critical threshold. With peak intensity forecast for November 2026~January 2027, the country is entering one of its most challenging water management periods in a decade — and the governance framework is only partly ready.

 

El Niño Is Here. This Time, Thailand Is Starting From Behind

On the last day of June 2026, Thailand's 35 major reservoirs held a combined 45 billion m3 of water which total up to 55% of total storage capacity, and 490 million m3 below the same date last year. Cumulative national rainfall since January had tracked roughly 12% below the seasonal average. The primary atmospheric indicator of El Niño that is the “Southern Oscillation Index” had already fallen to −13 across April and May. And on June 23, the ONWR Secretary-General chaired an emergency sub-committee meeting to order the nationwide activation of a Dynamic Operation Curve for all reservoir management authorities: store more, release less, prepare for drought.