Recent ensemble forecasts from models such as the ECMWF and GFS indicate Seoul’s June 28 maximum temperature will likely fall in the 27–29 °C range, driving the tight clustering of market-implied odds around those outcomes. Variability stems from uncertainty in afternoon cloud cover, boundary-layer moisture, and the precise timing of any weak frontal passage, all of which can alter peak readings by 1–2 °C. Historical climatology for late June shows a mean daily maximum near 28 °C, providing a baseline that traders weigh against the latest model runs. Official guidance from the Korea Meteorological Administration and updated high-resolution simulations expected over the next 48 hours will be the key catalysts likely to shift probabilities before the market resolves.