Global Seasonal Climate Update for June-July-August 2026

Following the transition to ENSO-neutral conditions at the end of the FMA 2026 season, the multi-model ensemble indicates a rapid transition to a strong El Niño event. By JJA 2026, the multi-model ensemble mean (MME) is forecast to comfortably clear the El Niño threshold, reaching approximately 1.8°C for the seasonal average. The intensification trajectory maintains a steep upward slope throughout the boreal summer and autumn (Figure 7). Spread among the individual member models is narrow during JJA, indicating very high forecast confidence. The Indian Ocean is forecast to experience development of the positive IOD phase, peaking concurrently with the intensifying Pacific El Niño. Starting from near-neutral conditions in May, the MME mean for the IOD seasonal average rises to approximately 0.4°C for JJA. Meanwhile, the equatorial Atlantic basin is expected to remain generally warm; SSTs in both the North and South Tropical Atlantic are predicted to stay slightly above normal.