Recent forecasts from the Korea Meteorological Administration and global models indicate a minimum temperature in Seoul on June 30 likely near 19–21°C, driven by rising humidity ahead of the East Asian monsoon, increased cloud cover limiting overnight radiative cooling, and warm southerly flow. These conditions differentiate close outcomes around 20–22°C, as small shifts in timing of showers or boundary-layer moisture can alter the daily low by 1–2°C. Historical climatology shows late-June lows averaging near 19–21°C, with urban heat island effects in Seoul often moderating extremes. Traders weigh ensemble spreads and upcoming model runs, which introduce the observed uncertainty between leading probabilities.