Trader consensus on a 25°C daily maximum for Seoul/Incheon on September 30 rests on official station observations from the Korea Meteorological Administration confirming that afternoon temperatures peaked at this level under mostly clear skies and light southwesterly flow. Late-September climatology supports highs near 23–26°C as seasonal cooling sets in, with model guidance and real-time reports aligning on no exceedance. Minor variations in localized readings or timing of any showers could theoretically shift the verified maximum by 1°C, yet the tight clustering of surface data and absence of stronger warming mechanisms make such adjustments unlikely before resolution.