Short-term ensemble forecasts from the China Meteorological Administration and global models like ECMWF project a daily high near 28°C for Guangzhou on May 18, driven by moderate subtropical ridge influence, partial cloud cover limiting peak solar insolation, and typical late-spring humidity levels that moderate diurnal temperature swings. This consensus keeps the 28°C outcome narrowly ahead at 29% implied probability, with 27°C close behind at 25.5%, as minor variations in boundary-layer moisture or afternoon convection could shift the exact maximum by 1–2°C. Historical May averages around 29–30°C provide baseline context, yet current steering patterns and lack of strong warm advection favor the slightly cooler cluster over higher outcomes above 29°C. Updated model runs and official observations in the next 48 hours will refine resolution criteria tied to the official station reading at Baiyun International Airport.