**Current numerical weather prediction models indicate a relatively modest peak temperature for Seoul on June 25, 2026, with ensemble guidance clustered around the mid-to-upper 20s °C.** This aligns with trader emphasis on the 26°C outcome (33% implied probability) as the modal expectation, followed by 27°C. Late-June climatology already features rising humidity and the onset of the East Asian monsoon, which tends to increase cloud cover and scattered showers that cap daytime maxima below the seasonal average of ~30°C. Key variables driving the spread include the precise timing and coverage of any frontal rain or low-level stratus on the 25th, which can suppress temperatures by 2–4°C relative to clear-sky scenarios. Steering flow and subtropical ridge strength will determine whether warmer air advection from the south occurs or whether a cooler maritime airmass dominates. Model disagreement between the Korean Meteorological Administration, ECMWF, and GFS ensembles remains notable at this 48–72-hour lead time, widening the probability mass across 25–29°C outcomes. Urban heat-island effects in central Seoul add a small positive bias to official station readings, while any organized convection tied to monsoon moisture could further limit the daily high. Updated model runs and KMA briefings over the next 48 hours are the primary near-term catalysts that could shift these market-implied odds.