**Forecast models for Tokyo on August 17 point to an overnight low near 23–24°C under typical midsummer conditions of high humidity and variable cloud cover.** Recent ensemble guidance from agencies including the Japan Meteorological Agency shows minimal deviation from August climatology, with average lows around 24°C, though scattered showers or thunderstorms could enhance or suppress radiative cooling overnight. High atmospheric moisture and the urban heat island effect limit temperature drops, keeping minima clustered tightly around these values. The narrow edge for 24°C over 23°C reflects minor model spreads in predicted wind patterns and precipitation timing between the evenings of August 16–17. Traders weigh these subtle variables against historical August variability, where clear skies allow slightly deeper cooling while clouds or rain hold temperatures higher. Updated model runs and official JMA briefings in the next 48 hours will likely narrow the range further ahead of resolution.