**Forecast models indicate that increasing cloud cover and scattered showers from a southerly moisture influx will moderate maximum temperatures in the Seoul-Incheon area on August 28, keeping them near the late-August climatological average of 29–30 °C.** Persistent high humidity and light easterly winds limit diurnal heating, while variable precipitation timing—particularly any midday or afternoon convective activity—introduces the 1–2 °C spread separating the closely matched 28 °C, 29 °C, and 30 °C outcomes. Stronger or earlier rain would favor the lower end by enhancing evaporative cooling and reducing insolation; clearer intervals would allow brief peaks near 31 °C. Recent heatwave conditions have eased with these changes, aligning trader-implied probabilities with ensemble guidance showing modest day-to-day variability rather than extreme outliers.