**Trader consensus on a 26°C high for Busan on October 1, 2026, rests on official Korea Meteorological Administration (KMA) observations and model guidance showing a daytime peak near that threshold.** Early October climatology for Busan features average highs of 22–25°C as cooler autumn air masses arrive from the north, replacing late-September warmth. On the day, partly cloudy skies, northwesterly winds of 5–10 m/s, and stable pressure supported gradual warming to a maximum consistent with 26°C in KMA station data. Minor model spread existed around afternoon mixing and sea-breeze effects, yet the aggregated readings aligned precisely with this outcome. A realistic shift would require an unforecasted surge in insolation or measurement revision pushing the official maximum to 25°C or 27°C, though current observational consensus makes that improbable before resolution.