Trader sentiment around the highest temperature in Busan on May 18 shows pronounced uncertainty, with implied probabilities spread across several outcomes and none exceeding 34%. Short-range ensemble forecasts from the Korea Meteorological Administration indicate a transient ridge of high pressure building over the southern peninsula, which could allow daytime highs to reach 28–30 °C depending on the exact timing of any passing weak frontal boundary. Key variables include the degree of cloud cover during peak insolation hours, boundary-layer mixing driven by southerly flow, and local sea-surface temperatures around 18 °C that moderate coastal warming. Historical May climatology for Busan places average daily maxima near 22 °C, yet recent model runs display modest positive anomalies. Updated guidance from the KMA is expected within the next 24 hours and will likely refine these probabilities ahead of final resolution.