Persistent rain and overcast skies on September 26 are expected to limit solar heating and keep Busan’s daytime maximum near 22–23°C, aligning with the tight market-implied odds between those two outcomes. Northeast winds and high humidity from the KMA forecast, combined with model runs showing widespread precipitation through midday, suppress temperatures below the late-September climatological average of roughly 25–26°C. Minor variations in rainfall timing or brief cloud breaks could allow a 24°C reading if insolation increases, while continued steady rain favors the lower end near 22°C. Official observations from the Korea Meteorological Administration will determine the exact peak.