Japan weather bureau sees 100% chance El Nino persists through autumn

According to data from May 2026, the sea surface temperature (SST) for the NINO.3 region was above normal with a deviation of +1.2°C. The five-month running mean value of the NINO.3 SST deviation for March 2026 was +0.4°C. SSTs across the equatorial Pacific were above normal, particularly in the central and eastern parts. Subsurface water temperatures also showed above-normal readings throughout the equatorial Pacific. Atmospheric conditions, including near-normal convective activity near the equatorial dateline and weaker-than-normal easterly winds over the central equatorial Pacific, further indicate the presence of El Nino conditions.

JMA's seasonal ensemble prediction system projects that the eastward propagation of warm subsurface water will maintain above-normal SSTs in the central and eastern equatorial Pacific. The NINO.3 SST is expected to rise and remain above normal until boreal autumn due to this ocean-atmosphere interaction. In contrast, the area-averaged SST in the tropical western Pacific (NINO.WEST) region was near normal in May and is likely to remain below normal until boreal autumn. The tropical Indian Ocean (IOBW) region's SST was below normal in May and is predicted to be below or near normal until boreal summer, then near or above normal until boreal autumn.

Weather conditions observed in May aligned with those seen in past El Nino events, including above-normal temperatures from Central America to the central equatorial Pacific.