Active southwest monsoon conditions and scattered thunderstorms over Metro Manila are the main drivers of uncertainty in the August 22 minimum temperature. Persistent cloud cover and rainfall reduce nocturnal radiative cooling, typically keeping overnight lows near the seasonal 24–26 °C range, while any breaks in the monsoon flow or lighter winds could allow greater cooling toward 22 °C or below. PAGASA’s extended outlook shows a 26 °C low with 70 % rain probability, but short-term model runs remain sensitive to the track of nearby disturbances and exact timing of heaviest showers. Traders are weighting these variables heavily, as even modest shifts in cloud thickness or wind speed can move the recorded minimum across the closely bunched market outcomes.