Latest forecast models from the Korea Meteorological Administration and global ensembles point to an overnight low in Seoul near 15–16°C on May 19, driven by a transient high-pressure ridge that limits cloud cover while allowing radiational cooling under light winds. Ensemble spreads arise mainly from uncertainty in the exact timing of a weak frontal passage and associated moisture advection, which could either suppress the minimum by 1–2°C through increased humidity or allow it to dip to 13°C or below if skies clear earlier than expected. Historical May climatology shows typical lows of 13–14°C, so current guidance sits slightly above average yet remains sensitive to small shifts in 48-hour model runs expected later today. Trader consensus reflects this narrow band of likely outcomes, with the tight clustering around 15–17°C underscoring the modest but real scientific uncertainty in short-range temperature predictions.