Recent Hong Kong Observatory guidance and multi-model consensus indicate overnight lows near 25–26 °C for August 4 amid scattered showers and persistent cloud cover associated with a broad trough of low pressure over the South China Sea. These conditions suppress radiative cooling under the humid summer monsoon regime, moderating minimum temperatures modestly below the August climatological mean of roughly 26.8 °C. Seasonal outlooks from the Observatory call for normal-to-above-normal temperatures overall, yet the near-term pattern of enhanced moisture and limited insolation favors the market’s leading probabilities clustered around 25 °C (36.5 %) and 26 °C (25.5 %). Lower thresholds such as 21 °C or below retain meaningful implied odds because any unexpected strengthening of the trough or heavier nocturnal rainfall could produce brief additional cooling, while probabilities above 27 °C remain low given current atmospheric moisture and steering patterns. Updated official forecasts and observational trends over the next 48 hours will be the primary drivers shifting these market-implied odds.