Northeasterly monsoon flow continues to moderate temperatures across northern Taiwan, with Central Weather Administration guidance and ensemble forecasts pointing to overnight lows of 23–26°C in Taipei on September 18. Persistent easterly breezes, partial cloud cover, and scattered light showers limit nocturnal radiative cooling while maintaining high humidity near 80–90%, keeping the minimum tightly clustered around 24–25°C. Model consensus shows little divergence on steering patterns or frontal passage timing, though small differences in cloud thickness or precipitation timing could shift the exact low by 1°C. Historical September climatology supports this range, with traders assigning near-equal weight to 24°C and 25°C outcomes reflecting the narrow uncertainty band in official guidance ahead of overnight observations.