Traders see 28–29°C as the most likely minimum temperature in Shanghai on July 16 because ensemble forecasts from the ECMWF and GFS models currently cluster around that range for the overnight period. Shanghai’s subtropical monsoon climate features high humidity that limits nocturnal radiative cooling, while urban heat-island effects and light southerly flow keep lows elevated compared with rural surroundings. Recent model runs show modest disagreement on the timing of any passing showers, which could either suppress or enhance cooling depending on cloud cover. Historical July climatology places average overnight lows near 26–28°C, so the tightly matched market probabilities reflect both the narrow forecast spread and the inherent uncertainty in short-range temperature guidance just two days out. New model cycles and official China Meteorological Administration updates will provide the next clear signals.