Recent short-range forecasts from the Korea Meteorological Administration indicate Seoul’s overnight minimum on May 18 will likely settle between 13 °C and 15 °C, driven by weak northerly flow behind a departing frontal system and clear skies that favor moderate radiative cooling. This places the 13 °C and 14 °C outcomes at the center of model consensus, while slightly warmer advection from the Yellow Sea keeps the 15 °C bucket competitive. Mid-May climatology for Seoul shows overnight lows typically spanning 12–16 °C, so the narrow spread in current probabilities reflects both normal spring variability and the limited lead time before resolution. Updated model runs and evening surface observations over the next 48 hours remain the key catalysts that could shift probabilities among these three tightly matched outcomes.