Persistent heavy rain and extensive cloud cover over Seoul and Incheon on August 31 are suppressing nocturnal radiative cooling, keeping overnight lows tightly clustered near 22–24 °C. Official guidance from the Korea Meteorological Administration and numerical models show sustained easterly flow, high humidity above 90 %, and widespread precipitation that limits temperature drops after sunset, with hourly readings holding steady around 23–24 °C through the early morning. Minor differences among leading outcomes hinge on the precise timing and intensity of the heaviest rain bands and any brief wind shifts, which could allow slightly more or less cooling before sunrise. Updated model runs and the ongoing frontal system reinforce this narrow range, consistent with trader-implied probabilities that treat 22 °C, 23 °C, and 24 °C as nearly equiprobable.