Seoul's summer nocturnal minimum temperatures hinge on clear-sky radiative cooling, boundary-layer humidity from the East Asian monsoon, and weak synoptic winds that limit mixing. With July climatological lows near 21–24 °C and current model guidance indicating modest cloud cover and light southerly flow for 10–11 July, the tight clustering of market-implied probabilities around 23–25 °C reflects uncertainty in the precise magnitude of overnight cooling rather than any dramatic shift in large-scale pattern. Urban heat-island effects and variable precipitation timing can easily add or subtract 1–2 °C from the observed minimum recorded between 03:00–09:00 local time, keeping the 22–26 °C band the focus of trader attention ahead of updated KMA and ensemble forecasts.