Recent observational data from sources like ERA5 and preliminary agency analyses position September 2026 global surface temperatures near 1.35–1.39°C above the 1850–1900 baseline, driving the dominant market-implied probability. A strengthening El Niño, with Niño 3.4 anomalies exceeding +2°C and approaching record levels by late September, has amplified warmth through enhanced Pacific heat release, consistent with historical analogs during strong events. Long-term anthropogenic forcing provides the underlying trend, while short-term factors such as reduced volcanic cooling and typical seasonal patterns limit upside deviation. Upcoming final NOAA and NASA releases will refine exact values within this narrow band, though model divergence and data revisions introduce modest uncertainty around the precise bin.