Recent ensemble forecasts from the China Meteorological Administration, ECMWF, and GFS models converge on a daily maximum near 27°C in Shanghai for May 18, driven by a persistent subtropical high-pressure ridge that promotes subsidence and clear skies while light easterly winds limit warm-air advection from the south. Moderate relative humidity around 60–70% and partial afternoon cloud cover further moderate daytime heating, aligning with climatological mid-May norms for the region where average highs fall between 25–28°C. Traders have priced the tight 26–28°C cluster highest because model runs show minimal spread in maximum temperature output, though slight revisions in boundary-layer moisture or wind speed could still shift the exact peak by one degree before resolution.