Official Korea Meteorological Administration forecasts point to a 33°C daytime maximum for the Seoul-Incheon region on August 18 under building high pressure and clearing skies after several days of monsoon showers, yet Polymarket odds cluster tightly around 29–30°C. Incheon’s coastal location typically introduces a moderating sea breeze that caps afternoon peaks 1–3°C below inland Seoul readings, especially with lingering humidity and variable winds. Recent model consensus shows modest daytime heating potential once clouds dissipate, but traders appear to weigh the risk that the official station high falls short of the broader forecast due to timing of peak insolation or localized cooling. Historical late-August baselines near 30°C further anchor sentiment, with the market assigning only slim odds to 32°C or higher despite the official guidance.