Persistent monsoon-driven moisture and forecast showers across the Pearl River Delta are the dominant factors capping daytime heating in Guangzhou. Multiple models indicate moderate rain and extensive cloud cover on August 3, reducing surface insolation and promoting evaporative cooling that typically limits highs to the 29–31 °C range. With climatological early-August averages near 32 °C under clearer skies, the current consensus reflects the expected suppression from convective activity and high dew points, which divert energy into latent rather than sensible heat. The near-even split between 30 °C and 31 °C odds captures remaining ensemble spread in rainfall timing, intensity, and any brief clearing that could allow an extra degree of warming, while lower probabilities for 32 °C or above account for the low likelihood of significant breaks in the cloud deck.