Trader consensus on Polymarket assigns 100% implied probability to a lowest temperature of 13°C in Shanghai on April 28, driven by confirmed morning observations from the official Xujiahui observatory registering exactly 13°C around dawn, with daytime readings holding steady above 14°C amid persistent cloud cover and light showers. This positioning reflects tight alignment across China Meteorological Administration guidance, GFS, and ECMWF model ensembles, which projected minima of 12–14°C under stable southerly flows and urban heat island effects mitigating radiative cooling—consistent with Shanghai's April climatological average low of 11–13°C but elevated by recent warmer anomalies. Realistic challenges include an improbable pre-midnight cold surge if skies unexpectedly clear, though current infrared satellite imagery shows sustained overcast conditions; final daily summary from CMA observations will confirm resolution shortly after local midnight.