Trader consensus on Polymarket overwhelmingly favors a highest temperature of exactly 15°C in Seoul on March 23, driven by the latest ensemble forecasts from the Korea Meteorological Administration (KMA) and global models like ECMWF, which converge on this precise peak amid mild southerly flows and stable high-pressure systems. Surface observations from recent days show daytime highs stabilizing around 13-14°C, with radiative cooling at night limiting extremes, aligning with Seoul's March climatology where averages hover near 12°C but anomalies this season push toward 15°C. Realistic challenges include an unanticipated foehn wind surge or urban heat island amplification nudging it to 16°C, though model uncertainty bands (typically ±2°C) and historical verification rates above 85% for KMA short-range outlooks make such shifts unlikely.