**Persistent thunderstorm activity and high humidity are keeping overnight lows tightly clustered around 26–28°C in Shenzhen.** Multiple forecast models and local meteorological guidance show widespread cloud cover and frequent rain on August 27, which limits nocturnal radiative cooling and keeps minimum temperatures near the prevailing dew point of approximately 25–26°C. Southwesterly winds and elevated moisture (humidity often exceeding 90% at night) further suppress temperature drops, while the subtropical monsoon regime maintains warm advection. Official outlooks indicate a high probability of thunderstorms, with some areas potentially seeing heavy rain that could slightly modulate the exact low depending on timing and intensity. This scientific uncertainty—primarily from variable cloud cover, precipitation timing, and minor model differences in boundary-layer moisture—explains why trader-implied probabilities remain closely bunched, with 27°C edging the field at 33.5% amid the 26–28°C range. Newer model runs or radar trends on the 27th itself will likely refine the precise minimum.