Recent observational data from agencies including Copernicus ERA5 and preliminary NOAA analyses have placed September 2026 global mean surface temperature anomaly near 1.63°C above the 1850-1900 pre-industrial baseline in leading datasets, yet Polymarket traders show overwhelming consensus on the 1.35–1.39°C bin. This positioning reflects resolution criteria tied to a specific official index or adjusted baseline, reinforced by persistent El Niño-driven sea surface temperature records, above-average land and ocean heat, and model agreement on minimal month-to-month variability. Final agency reports or measurement revisions could shift outcomes if they diverge from current preliminary values or apply different homogenization methods.