Recent ensemble forecast runs from global and regional models highlight persistent monsoon-driven cloud cover and scattered heavy rainfall over Guangdong, suppressing maximum temperatures and clustering the most likely daily highs for Guangzhou around 28–30°C on June 17. These conditions, typical of the East Asian summer monsoon, limit surface heating through reduced solar insolation and evaporative cooling from precipitation, keeping peaks modestly below the June climatological average of 31–32°C. Scientific uncertainty stems from timing and intensity of convective cells, with small differences in model physics producing the narrow spread reflected in the closely matched market-implied probabilities. Updated short-range guidance from the China Meteorological Administration and ECMWF runs expected in the next 24–48 hours will provide the key data shifts traders are monitoring ahead of resolution.