Persistent cloud cover, widespread thunderstorms, and heavy rainfall across northern Taiwan have suppressed both daytime highs and overnight radiative cooling in Taipei on August 21, keeping the daily minimum near or below long-term August averages of 26–27 °C. Multiple forecast models show the overnight low hovering between 24–26 °C amid high humidity and light winds, with limited clear-sky periods that would otherwise allow greater temperature drops. Traders have assigned the highest implied probability (45 %) to 21 °C or below because recent model runs and real-time observations indicate the potential for slightly cooler pockets if rain persists through the early morning hours, while the clustered probabilities around 23–25 °C reflect the narrow scientific uncertainty range typical for a day with stable steering patterns and no major frontal passages.