Current numerical weather prediction ensembles show Shanghai's June 28 high most likely near 27–28 °C, with the tight spread between these outcomes reflecting modest differences in simulated cloud cover, boundary-layer mixing, and steering flow from the western Pacific subtropical high during the late Meiyu period. Official guidance from sources such as the China Meteorological Administration and global models (ECMWF, GFS) currently favors partly cloudy to overcast conditions that limit daytime heating while humidity remains elevated. Small revisions in forecast timing of any passing disturbances or changes in low-level wind direction could shift the peak by 1 °C, sustaining the close market split until the final 24–48 hours before resolution.