Recent ensemble forecasts from the Japan Meteorological Agency and global models point to radiative cooling under mostly clear skies and light winds as the main driver pushing the lowest temperature in Tokyo on May 24 toward the 13–14 °C range. These conditions favor stronger overnight heat loss compared with typical late-May climatology, where minimums average near 15 °C. Uncertainty in low-level cloud cover and any weak frontal passage creates the tight clustering around 13–15 °C outcomes, with slightly warmer solutions possible if moisture increases. Updated model runs in the next 48 hours will narrow the spread as the event approaches.