Persistent cloud cover, scattered showers, and the humid summer monsoon pattern over Hong Kong are limiting nighttime radiative cooling and anchoring the minimum temperature near 25 °C on August 4, according to the latest Hong Kong Observatory guidance and multi-model consensus. Seasonal climatology places typical August overnight lows at 26–27 °C, yet current atmospheric conditions—driven by lingering moisture and reduced insolation—have shifted the distribution slightly cooler, elevating the 25 °C outcome to a 65.5 % market-implied probability. The 26 °C and 24 °C bands capture residual forecast uncertainty around the precise timing and intensity of showers, while probabilities below 24 °C or above 27 °C remain low given model agreement and the absence of strong cold-air advection or clear-sky radiative episodes. Updated HKO briefings and regional model runs over the next 48 hours will be the key data releases that could refine these trader-assessed odds.