A strong El Niño event, with Niño 3.4 sea surface temperatures exceeding +2.8°C in September 2026 and forecasts for further intensification, represents the dominant driver behind current trader sentiment for the September global temperature anomaly. This oceanic warming, combined with elevated baseline conditions from prior years, supports model projections placing the monthly anomaly near 1.35–1.39°C above pre-industrial levels—the bin holding 51% implied probability. Recent ERA5 and Copernicus data confirm August 2026 reached 1.65°C, yet seasonal cooling and ensemble runs indicate September will moderate slightly while remaining well above historical norms. Key upcoming releases from NOAA and ECMWF will refine these estimates ahead of final resolution.