**Cloud cover, precipitation timing, and wind patterns over the next 48 hours are the dominant drivers of overnight radiative cooling at Incheon International Airport, which records the official Seoul-area minimum.** Forecasts from multiple models place the September 1 nighttime low in the 21–25 °C range, with consensus clustering around 22–23 °C. Persistent high humidity and scattered showers or thunderstorms—remnants of late-summer monsoon influence—limit clear-sky cooling, while light variable winds (generally 2–6 m/s) reduce mixing that could otherwise moderate temperatures. Recent days have featured tropical-night conditions with minima near or above 24 °C, but a modest northerly shift and partial clearing expected Tuesday night should allow slightly greater heat loss, supporting the tight market split between 22 °C and 23 °C. Model disagreement on exact shower coverage and timing, plus the microclimate difference between the coastal airport and urban Seoul, keeps the two leading outcomes nearly even. Updated runs from the Korea Meteorological Administration and global ensembles over the next 24 hours will likely resolve the narrow gap.