**Persistent southwest monsoon (habagat) flow, widespread cloud cover, and frequent thunderstorms are keeping overnight temperatures in Manila stable in the mid-20s °C for September 5.** Official and model guidance from sources such as PAGASA, GFS, and ECMWF consistently point to overnight lows near 25–26 °C (roughly 77–79 °F), with some runs showing brief dips to 24 °C under heavier rain and others holding at 26–27 °C where skies remain overcast but winds stay light-to-moderate from the west-southwest. High humidity (85–95 %), thick cloud decks, and steady precipitation suppress radiative cooling, limiting how far temperatures can fall after sunset. Historical September climatology places typical Manila lows around 25–26 °C, providing a baseline that aligns with current model output and explains why the 24 °C, 25 °C, and 26 °C outcomes dominate market pricing at roughly 30–32 % each. The close clustering of probabilities reflects genuine forecast uncertainty in the exact minimum—small differences in timing or intensity of rain bands or wind shifts can shift the recorded low by 1 °C. No major tropical cyclone or abrupt pattern change is expected in the next 24–48 hours, so the market-implied odds primarily capture this narrow band of typical rainy-season variability rather than any outlier scenario. Updated model runs and official PAGASA briefings ahead of the overnight period remain the key near-term catalysts that could nudge probabilities among the leading outcomes.