Recent forecast consensus from Chinese meteorological agencies and global models points to persistent cloud cover and rainfall on September 28 as the main factor capping Shanghai’s daily maximum near 27–28 °C. Northeast winds and an approaching frontal system are expected to limit solar heating while adding moisture, keeping surface temperatures below late-September climatological averages of roughly 28 °C. Model runs show only modest spread around these values, with the highest credible outcomes clustered at 27 °C (market-implied 45.5 %) and 28 °C (27.5 %). Updated guidance issued in the next 24–48 hours will determine whether any clearing allows a brief spike toward 29 °C or whether heavier rain further suppresses the peak.