Recent forecasts from numerical models indicate Taipei's overnight low on September 21 will likely settle near 23°C under mostly clear skies, light northeast winds, and moderate humidity levels typical of the late-summer transition. Subtropical radiative cooling overnight, combined with minimal cloud cover and stable high pressure, supports this range, while the urban heat island and proximity to the coast limit further drops. Minor model differences in boundary-layer mixing and any scattered afternoon showers could shift the exact minimum by 1–2°C, explaining the tight clustering around 23–24°C in trader positioning versus lower or higher outliers. Updated Central Weather Bureau guidance and next model runs will clarify resolution criteria based on official station readings.