**Forecast models from sources like the Japan Meteorological Agency and GFS indicate Tokyo’s overnight low on October 13 will likely settle near 18–19°C under partly cloudy skies, light northerly winds, and high pressure favoring radiative cooling.** Recent observations show similar conditions with minimums of 16–18°C, and the current setup lacks strong frontal systems or significant moisture that could alter cooling rates. Trader consensus clusters on 18°C and 19°C because small differences in cloud cover timing or wind speed across ensemble runs can shift the exact minimum by 1°C. Historical October averages for the date sit around 16°C, but the ongoing mild pattern supports the higher market-implied range while leaving room for last-minute adjustments from updated model guidance.