Strong northwest cold air advection following widespread autumn rainfall has driven the market's 95% implied probability on a 15°C minimum for Seoul/Incheon on October 13. Official forecasts from sources such as the Korea Meteorological Administration and ensemble models show overnight temperatures stabilizing near 15°C after daytime highs near 20–21°C, consistent with post-frontal cooling and clear skies developing by evening. Historical October climatology for the region supports lows in this range after similar frontal passages. The positioning could shift only if late-day observations or revised model runs register a meaningfully warmer or cooler minimum outside the 14–16°C window, though current data consensus makes that outcome unlikely before resolution.