Persistent cloud cover and widespread rain expected across the Seoul-Incheon area on August 31 are limiting overnight radiative cooling and keeping the diurnal temperature range narrow, with multiple forecast models converging on a minimum near 22–23 °C. This aligns with the 1991–2020 climatological nighttime low of roughly 22–23 °C for late August while the current humid, overcast regime suppresses both extreme warmth and sharp drops below seasonal norms. Official guidance from the Korea Meteorological Administration and international ensembles shows no significant cold-air advection or clear-sky conditions that would push readings to 21 °C or lower, supporting the market’s heavy weighting toward the 22 °C and 23 °C bins. Updated model runs over the next 24–48 hours will refine the exact minimum ahead of resolution.