A strong El Niño event, with Niño 3.4 anomalies already exceeding +2.7°C and forecast to peak near or above prior records, is the dominant near-term driver elevating September 2026 global mean surface temperatures above the long-term anthropogenic baseline. Official analyses show August 2026 tying the all-time monthly record at +1.65°C relative to 1850–1900, with early September observations and ensembles projecting a comparable or slightly higher anomaly as the event’s influence builds. Key differentiating factors among the closely matched market bins include the precise lag between Pacific SST peaks and global response, regional cloud and circulation feedbacks, and minor model divergences in the timing of intensification. Final Copernicus and NOAA monthly aggregates, typically released mid-October, will resolve the outcome amid inherent short-term variability around the elevated central tendency.