**Persistent southwest monsoon activity (habagat) is the dominant driver keeping Manila’s overnight minimum temperature tightly clustered around 25–27 °C on 27 August.** Active moisture transport from the southwest, combined with scattered to widespread thunderstorms and extensive cloud cover, limits nocturnal radiative cooling under high humidity and moderate-to-strong winds. Official PAGASA guidance and model consensus show mostly cloudy to overcast skies with rain showers continuing through the night, which prevents the clear-sky radiative losses that would otherwise allow temperatures to fall into the low 24 °C range or below. Recent developments reinforcing this pattern include two low-pressure areas expected to enter the Philippine Area of Responsibility, further enhancing monsoon rainfall and cloudiness across Luzon. Historical climatology for late-August Manila nights under similar monsoon regimes also centers on 25–27 °C lows, with urban heat-island effects adding a slight upward bias. The near-even market distribution across 25 °C, 26 °C, and 27 °C therefore reflects genuine forecast uncertainty in the precise timing, coverage, and intensity of overnight convection rather than any single deterministic outcome. Resolution will hinge on the final observed minimum at official stations (typically recorded in the pre-dawn hours), where small differences in cloud breaks or rainfall timing can shift the reading by 1–2 °C.