Recent Korea Meteorological Administration short-range forecasts and ensemble guidance center Seoul’s May 17 overnight minimum near 15–16 °C under mostly clear skies and light winds, aligning with the tight market spread between 14 °C and 15 °C. Radiative cooling overnight will be modulated by any residual afternoon cloud cover that traps longwave radiation, potentially lifting the low toward 17 °C, while fuller clearing and calmer boundary-layer conditions could enhance surface cooling and push readings to 13–14 °C. Mid-May climatology shows typical lows of 12–15 °C, so the current model consensus reflects modest variability rather than extremes. Updated KMA runs and real-time observations through tonight remain the decisive inputs that could shift probabilities among these tightly clustered outcomes.