Trader consensus has coalesced around 28°C as the official daily maximum for Busan on September 19 because Korea Meteorological Administration observations reached a peak of 28.6°C during afternoon hours under partly cloudy skies and steady northeast winds of 10–15 m/s. This aligns with model consensus from GFS and ECMWF runs showing limited daytime heating capped near 27–28°C amid moderate humidity and no significant advection of warmer air. The market-implied 100% probability for exactly 28°C reflects traders’ confidence that the KMA station reading will resolve at or immediately adjacent to this threshold once final quality-controlled data are posted. A realistic challenge would require either a revised station maximum falling to 27°C from measurement adjustments or an unexpected late-day spike pushing the official high to 29°C, both of which appear improbable given the current observed trajectory and stable synoptic pattern.