Persistent cloud cover, scattered showers, and northeasterly winds are keeping Tokyo's overnight radiative cooling limited on August 29, anchoring the lowest temperature near 21–22 °C. High humidity and light rain reduce the diurnal temperature range by releasing latent heat and suppressing clear-sky heat loss, while the urban heat island effect adds a modest warming bias to minimum readings. Recent model consensus from the Japan Meteorological Agency and global ensembles shows only small differences in cloud timing and wind strength that could shift the low by 1 °C, producing the tight market clustering around 21 °C (37 %) and 22 °C (37.5 %). Any late-night clearing or stronger onshore flow would favor the lower outcome; sustained overcast favors the higher.