Tokyo's late-July overnight lows typically hover near 24–26°C under the influence of the North Pacific subtropical high, which promotes clear skies and moderate radiative cooling after daytime peaks near 32–34°C. Recent Japan Meteorological Agency guidance and ensemble models indicate persistent high humidity (70–85%) and light easterly winds that limit nocturnal temperature drops, while urban heat island effects from the Tokyo metropolitan area further elevate minimum readings by 1–2°C compared with rural analogs. Scattered showers or increased cloud cover in the 48-hour window could suppress cooling and push the lowest reading toward 27–28°C, whereas clearer conditions would favor 24–25°C outcomes. With model spreads remaining narrow and no major synoptic shifts expected before resolution, trader probabilities cluster tightly around these thresholds.