Forecast models from the Korea Meteorological Administration and global ensembles indicate Busan daytime highs on June 13 will likely peak in the 26–29 °C range under early-summer conditions, with the market’s tight clustering around 27–29 °C reflecting modest uncertainty in cloud cover and sea-breeze timing. Coastal moderation from the East Sea keeps temperatures lower than inland areas, while increasing humidity and possible overcast skies reduce solar heating and cap afternoon maxima. Recent model runs show limited day-to-day shifts, consistent with climatological norms for mid-June when the East Asian monsoon begins to influence the region. Resolution hinges on the precise maximum recorded between 9 a.m. and evening, sensitive to wind shifts and any weak frontal passage that could alter insolation by a few degrees.