Korea Meteorological Administration guidance currently points to a daytime maximum of 24–25 °C in Seoul on May 17, driven by a strengthening high-pressure ridge that promotes subsidence, clear skies, and modest southerly warm-air advection over the Yellow Sea. This setup lifts temperatures just above the mid-May climatological average of 22–23 °C, explaining why trader probabilities cluster tightly around the 24 °C, 25 °C, and 23 °C outcomes. Minor variations in advection intensity, boundary-layer mixing, or afternoon insolation could nudge the peak by a degree in either direction, which keeps the 26 °C-or-higher bucket viable while colder thresholds remain remote. Market focus now centers on the next model run and any adjustments to ridge positioning before official readings are finalized.