Trader consensus on Polymarket reflects tight uncertainty in Busan’s diurnal temperature peak, with KMA short-range forecasts showing clear skies and light easterly winds driving highs to 25–26°C through enhanced solar insolation, slightly above the May climatological average of 22°C. Morning temperatures around 19–20°C have risen steadily under high pressure, but coastal sea breeze development—expected mid-afternoon—poses the key differentiator: early onset could cap the maximum at 24°C via cool marine air advection, while delay favors 26°C or brief 27°C spikes. Ensemble model spread highlights this 1–2°C variability, with official hourly observations from Korea Meteorological Administration stations resolving the market by midnight. Next KMA update at noon may sharpen odds.