Official forecasts from the Korea Meteorological Administration and global numerical weather prediction models have converged on an overnight low near 16°C for Seoul on May 25, underpinning the market’s near-certain pricing for that outcome. Springtime radiative cooling under clear to partly cloudy skies and light winds supports this level, consistent with recent model runs showing minimal deviation from seasonal norms around 13–14°C historical averages. Traders appear to weigh the tight clustering of ensemble guidance and the low likelihood of late-day frontal shifts or anomalous moisture that could drop readings further. Minor forecast revisions from updated KMA briefings remain the main variable that could introduce uncertainty before final observations are recorded.