Recent forecasts from the Japan Meteorological Agency and international models indicate persistent cloud cover, heavy thunderstorms, and a frontal boundary over Tokyo on September 7, moderating overnight radiative cooling and supporting minimum temperatures near 21–24 °C. High humidity and sustained southerly flow limit the potential for sharp drops below 20 °C, while model spread in precipitation timing creates uncertainty around whether the low settles at 23 °C or edges toward 24 °C. Traders assign the highest implied probability to 23 °C because ensemble guidance clusters there, yet the sizable share on 19 °C or below reflects residual risk if clearer skies develop late in the night. Updated model runs and official advisories over the next 48 hours will refine these thresholds ahead of market resolution.