Recent forecasts from sources including the Korea Meteorological Administration and international models indicate clearing skies over Incheon and Seoul after Chuseok-period rain on September 25–26, supporting radiative cooling under partly cloudy to clear conditions overnight into September 27. This setup favors minimum temperatures near 18°C, consistent with the market's leading 54% implied probability, as daytime highs moderate to 24–26°C amid light westerly winds and dew points around 18–19°C. Historical September climatology shows typical overnight lows of 14–16°C, but current model consensus and post-frontal stabilization have shifted trader sentiment toward the upper end of that range. Updated runs from GFS and ECMWF on the 26th will likely refine the exact minimum before resolution.