Current forecasts from the Japan Meteorological Agency and supporting models indicate Tokyo’s overnight minimum on June 14 will settle at 21 °C under stable high pressure and light northerly flow. This aligns with the seasonal transition out of the rainy season, when typical daily lows range 19–22 °C, and recent model runs show minimal spread around that value. With official observations now confirming the threshold and little time remaining before market resolution, traders have converged on 21 °C at essentially 100 % implied probability. Only an unexpected late surge in cloud cover or a localized urban-heat-island anomaly could push the reading outside the implied band, though neither is supported by current data.