A rapidly strengthening El Niño in the equatorial Pacific, with Niño 3.4 anomalies reaching approximately +2.8 °C by mid-September 2026 and forecasts pointing to a potential record peak near +3.5–4.0 °C later in the year, represents the dominant near-term driver elevating September global mean surface temperatures. This event builds on the long-term anthropogenic warming trend of roughly 0.2 °C per decade, pushing monthly anomalies into the 1.35–1.44 °C range above the 1850–1900 baseline according to recent agency analyses. July and August 2026 already registered at 1.56 °C and around 1.65 °C respectively in multiple datasets, with the El Niño’s influence expected to sustain elevated readings through the Northern Hemisphere fall even as the full global response lags the Pacific peak by several months. Model consensus from NOAA, ECMWF, and others shows high confidence in very strong El Niño conditions through year-end, though exact September values hinge on final observational adjustments and any short-term variability in ocean-atmosphere coupling or regional patterns such as the Indian Ocean Dipole. The narrow spread between the leading market bins reflects this mix of confirmed strong forcing and residual uncertainty in monthly resolution criteria.