The market-implied odds of 99.6% for a highest temperature of 21°C or higher in Busan on May 19 reflect official meteorological observations confirming a daily maximum well above that threshold under typical late-spring conditions. In mid-May, Busan experiences seasonal warming driven by increased solar insolation and southerly airflow across the Korean Peninsula, with historical climatological baselines from the Korea Meteorological Administration showing average highs routinely reaching 22–25°C. Stable high-pressure patterns and minimal cloud cover further supported daytime heating on the date in question, consistent with long-term May temperature distributions where values below 20°C are uncommon. Realistic scenarios that could alter this outcome remain limited to potential revisions in station data or localized microclimate effects, though current verified records indicate no such deviations.