Recent Japan Meteorological Agency forecasts and ensemble models indicate Tokyo's overnight minimum on August 27 will likely fall between 24–26°C, with scattered showers and increasing cloud cover expected to moderate nocturnal radiative cooling. High humidity and light winds further limit temperature drops by reducing heat loss from the urban surface, while the Pacific high-pressure influence maintains warm advection. These factors create tight clustering around the leading 25°C and 26°C outcomes, as minor shifts in shower timing or cloud thickness can alter the low by 1°C. Historical August climatology shows typical lows near 24–25°C, but above-normal seasonal temperatures add slight upward pressure. Updated model runs and JMA briefings through August 26 will provide the next key data points for traders.