Recent ensemble forecasts from the ECMWF and GFS models indicate a daytime maximum near 28°C in Guangzhou on May 17, driven by persistent subtropical warmth from a weakening high-pressure ridge over southern China combined with increasing afternoon cloud cover and scattered thunderstorms. These conditions moderate peak heating while keeping temperatures above the seasonal baseline of 26–27°C for mid-May. Model runs show minor spread between 27–29°C depending on exact timing and intensity of convective activity, with official monitoring at Guangzhou Baiyun International Airport serving as the resolution source. Traders assign the highest probabilities to 28°C and 29°C because new observational data and updated guidance continue to favor this narrow range, though any delay in storm development or clearer skies could shift the outcome toward the upper end.