Short-term forecast uncertainty two days ahead drives the closely matched 50% probabilities across 32–35°C highs for Busan on August 24. Late-August conditions under the North Pacific High typically deliver southerly flows with daytime maxima near 30°C, moderated by coastal sea breezes and high humidity around 70–80%. Ensemble model spreads arise from minor differences in cloud cover reducing insolation, subtle shifts in steering winds, or isolated showers that could cap temperatures at the lower end versus clearer skies allowing peaks near 35°C. Historical August averages hover at 29–31°C, with occasional excursions above 34°C during stronger subtropical ridge influence, leaving traders weighting the central range while assigning low odds to extremes outside it.