Traders have converged on 31°C as the day's official high in Tokyo due to Japan Meteorological Agency station data showing a peak near that threshold during afternoon hours under partly cloudy skies and southerly flow. Current evening observations around 27°C with rising humidity and light rain confirm the maximum has passed, aligning with model runs that incorporated regional heat advection without extreme anomalies. Historical September baselines for the urban heat island effect further contextualize this outcome. A late revision in verified maximum readings or boundary adjustments by monitoring agencies could still shift resolution, though proximity to day's end limits such scenarios.