Recent forecast models from the Korea Meteorological Administration indicate mild spring conditions across the Korean Peninsula, with Seoul’s overnight lows most likely settling in the 15–17°C range on May 20 due to moderating northerly flow and limited cloud cover. These temperatures align with climatological averages for late May, when radiative cooling under clear skies typically produces the day’s minimum just before dawn. Key variables that could shift outcomes by a degree or two include the precise timing of any weak frontal passage, local wind speeds that enhance or suppress urban heat retention, and minor model disagreements on boundary-layer moisture. Updated guidance issued in the next 48 hours will refine the exact minimum, as ensembles currently show only modest spread around this central tendency.