**Official observations from the Japan Meteorological Agency confirm a daily maximum of 23°C in Tokyo on September 12, 2026, under cloudy skies with light rain and northeast winds that limited daytime heating.** Recent model runs and station data align closely with this value, reflecting typical early-September conditions near the seasonal average of roughly 23–25°C and showing no late surge from clearer skies or southerly flow. The market’s near-certain pricing for 23°C reflects real-time verification of recorded highs across central Tokyo stations, with minimal dispersion in official reports. Only an unusually large post-observation correction or station-specific discrepancy would shift the outcome, though current data consistency makes such revisions improbable.