NOAA declares El Nino on June 11 as the Pacific moves from La Nina with Nino 3.4 reaching plus-1.7 degrees Celsius

Summary

The US National Oceanic and Atmospheric Administration issued an El Nino Advisory on 11 June 2026, officially declaring that El Nino conditions had developed in the tropical Pacific after the La Nina phase that peaked in late 2025. The Nino 3.4 sea surface temperature (SST) index, covering a key region of the central equatorial Pacific, rose from +0.48°C averaged over March-May 2026 to +0.94°C in May and reached +1.7°C in the weekly reading centred on June 17. NOAA gives a 63% probability that SSTs will exceed the 2.0°C threshold defining a very strong El Nino event by autumn 2026, with further intensification through Northern Hemisphere winter 2026-27. The rapid transition from La Nina to a potentially very strong El Nino in a single year is unusual and has direct consequences for global precipitation patterns, Atlantic hurricane activity, West Africa monsoon variability, and Australian rainfall.

The split

US weather and climate media focused on the implications for the 2026 hurricane season, where El Nino's wind shear effects reduce Atlantic storm formation, and for the US Pacific Northwest wheat crop, where an El Nino winter typically brings drier-than-normal conditions. Australian media tracked the potential for a return of El Nino-associated drought after two La Nina wet years. South Asian coverage noted implications for the Indian monsoon, which El Nino can suppress in some configurations. African climate organisations highlighted impacts on East Africa and the Sahel, where El Nino tends to produce mixed effects on different sub-regional precipitation regimes. Indonesian and Philippine media tracked potential drought risks for the upcoming agricultural season.

By the numbers

• June 11, 2026, date NOAA issued the El Nino Advisory
• +1.7°C, Nino 3.4 SST anomaly in the June 17 weekly reading
• 63%, NOAA probability of exceeding 2.0°C (very strong El Nino threshold) by autumn 2026
• +0.48°C, March-May 2026 Nino 3.4 average SST anomaly (La Nina threshold is below -0.5°C)
• La Nina conditions prevailed through late 2025 before the rapid transition

Why it matters

The speed and potential strength of the 2026 El Nino event is significant because it follows two consecutive La Nina years and because a very strong or historically strong event has global consequences: droughts in Australia, Indonesia, the Philippines, and southern Africa; flooding in the southwestern US and Peru-Ecuador; altered Atlantic hurricane tracks; and impacts on global crop production. For food security assessments, a very strong El Nino arriving during an already tight global corn stocks environment amplifies the tail risk. The event's timing also affects the 2026 West Africa Sahel rainy season and the 2026-27 South Asian monsoon.

What to watch

• NOAA monthly ENSO diagnostic discussions through autumn and winter 2026
• Whether the 2026 El Nino reaches 2015-16 intensity levels (the historical benchmark for very strong events)
• Crop condition updates from Australia, Indonesia and South Africa as El Nino-associated dryness develops
• Atlantic hurricane season tracking from August through November 2026