Research notes and updates from the team.
IRI’s NDJ 2026/27 outlook, shaped by a very strong El Niño (Niño 3.4 at +2.84°C in September, +3.3°C weekly) and a positive IOD, favors drier-than-normal conditions in northern South America, Central America, South Africa and Southeast Asia, and wetter conditions in the southern U.S., Uruguay and the Middle East. Above-normal temperatures are likely across most of the globe.
Read more →The forecast shows increased chances of below-normal rainfall in northern South America, Central America, South Africa, SE Asia, and the Maritime Continent, expanding to Alaska, NW Australia, and Madagascar by DJF–JFM. Above-normal rainfall is likely in the southern US, Uruguay, NE Africa, the Middle East, and parts of Eurasia—patterns broadly tied to strengthening El Niño conditions.
Read more →During July 2026, sea surface temperature (SST) anomalies increased further across the central and eastern equatorial Pacific Ocean. The monthly Niño 3.4 index reached +2.03 °C, marking the transition of the ongoing El Niño event into the very strong category.
Read more →During June 2026, sea surface temperature (SST) anomalies increased further across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index reaching +1.55 °C.
Read more →During May 2026, sea surface temperature (SST) anomalies increased further across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index reaching +0.94 °C.
Read more →During April 2026, sea surface temperature (SST) anomalies rapidly warmed across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index reaching 0.47 °C. Over the past four weekly Niño 3.4 index observations (15 April to 06 May), values ranged from +0.5 °C to +0.9 °C, indicating that short-term conditions remained consistently above the El Niño threshold.
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