Current forecast models, including GFS runs, project a stable high-pressure regime over Busan on September 16 with northeast winds of 10–17 mph, partly cloudy skies, and no significant frontal passages or moisture influx. This setup supports overnight radiative cooling leading to a minimum near 20–22°C, aligning with climatological September lows of about 21°C. Trader balance between the 25°C-or-higher and 15°C-or-below outcomes stems from model spread in exact minimum timing and boundary-layer mixing, with recent observations showing consistent 21–22°C readings and limited diurnal variability. Updated model guidance expected within 24 hours will likely narrow resolution criteria around these thresholds.