Recent forecast models from agencies like the Korea Meteorological Administration and international sources show a daily minimum temperature in the Seoul-Incheon area on September 25 likely falling between 18–21°C, driven by an approaching weather system bringing southerly winds, increased cloud cover, and rain that limits overnight radiative cooling. Recent late-summer warmth has kept daytime highs near 27–29°C, but a gradual seasonal transition and expected precipitation are moderating nighttime lows compared to prior clear, dry conditions. Trader sentiment remains closely divided across the 15–20°C range because ensemble models diverge on exact timing of the rain band and wind shifts, which can alter the minimum by 1–2°C; updated runs and official observations closer to resolution will likely refine these market-implied probabilities.