Numerical weather models from global ensembles show strong consensus for Shanghai’s overnight minimum temperature on June 12 settling near 21 °C, reflecting typical early-summer subtropical conditions with moderate humidity and limited radiative cooling overnight. Official guidance, including recent runs from agencies such as the China Meteorological Administration and international centers, clusters tightly between 20–22 °C, aligning with historical June averages for the region and supporting the market’s overwhelming 99.8 % implied probability on the 21 °C outcome. Minor deviations remain possible if unexpected cloud cover changes or localized wind shifts alter nocturnal cooling rates, though current observational trends and ensemble spread indicate low likelihood of crossing into adjacent bins before resolution.