Global Seasonal Climate Update for October-November-December 2026
Outlook for Oceanic Drivers for the Next Season: For the October-November-December 2026 (OND 2026) season, multi-model ensemble forecasts indicate a further intensification toward stronger El Niño conditions. The seasonal average Niño 3.4 SST anomaly is forecast to reach approximately +3.7°C during OND 2026, with the warming trend peaking around December 2026. The spread among individual forecast systems generally remains narrow, reflecting high forecast confidence.
In the Indian Ocean, a positive IOD is predicted to peak in October 2026 and then decline yielding a seasonal mean anomaly for OND 2026 of +0.5oC. Meanwhile, the equatorial Atlantic basin is forecast to remain warm, with SSTs in both the North and South Tropical Atlantic staying above normal.
About the Global Seasonal Climate Updates series
The Global Seasonal Climate Update (GSCU) is WMO's flagship seasonal climate outlook, providing authoritative information on the current state of the climate system and expected temperature and rainfall patterns for the coming three months. Issued monthly, the GSCU brings together the latest global climate science to support informed decision-making worldwide.
