**Persistent monsoon-driven rainfall and high humidity are anchoring trader expectations for Guangzhou’s overnight low on August 28 near 25–27 °C.** Multiple forecast sources project a low of 26–28 °C amid widespread cloud cover, scattered thunderstorms, and light winds, which limit radiational cooling. These conditions align with the historical average low of ~25 °C for the date and typical late-August patterns in the Pearl River Delta, where moisture from the East Asian monsoon suppresses both extremes. Model outputs show minor spreads—some runs favor slightly cooler readings near 25–26 °C if heavier overnight rain occurs, while others edge toward 27–28 °C with partial clearing or warmer advection. This uncertainty keeps the market tightly bunched across 25–27 °C outcomes. Official station data (likely from a central Guangzhou or Baiyun site) will determine resolution, and any late-model shift in precipitation timing or wind could quickly reprice the tightly contested range.