Recent forecasts from the Korea Meteorological Administration and ensemble models point to a daily maximum near 28–29°C in Seoul on June 18 under weak high pressure and modest warm advection. Traders assign the highest implied probabilities to these outcomes because daytime heating will be modulated by variable afternoon cloud cover, light southerly winds, and boundary-layer humidity levels near 60–70 percent, which can trim peak readings by 1–2°C if thicker clouds develop. Historical early-summer analogs show similar setups often produce highs clustered tightly around the monthly climatological mean of 27–28°C, with small differences in insolation timing or localized sea-breeze effects creating the narrow spread between 27°C and 30°C bins. Updated model runs tomorrow morning will likely refine these probabilities ahead of market resolution.