Persistent rain, extensive cloud cover, and northerly winds associated with a stationary front and nearby low-pressure influences are suppressing Tokyo's maximum temperature on September 26, 2026. Official Japan Meteorological Agency guidance and ensemble models from multiple centers converge on a high near 21–24°C under overcast, wet conditions, well below September climatological averages around 26°C. This setup favors 23°C as the most likely outcome per aggregated trader assessments, with limited upside potential absent unexpected clearing or southerly flow shifts before peak heating. New model runs and observational updates overnight will refine the precise threshold for market resolution.