Forecast models for Manila on September 13 point to overnight lows of 24–26°C as the dominant range, driven by the southwest monsoon’s persistent cloud cover, high humidity near 90%, and scattered showers that limit radiative cooling overnight. Light northerly winds and stable pressure around 1010–1012 hPa further moderate temperature drops, keeping the minimum near typical September climatology of roughly 25–26°C. Traders assign the highest implied probabilities to 25°C and 26°C because ensemble guidance shows only modest day-to-day variability, with 24°C possible if clearer skies allow slightly greater cooling before dawn. Resolution hinges on the precise 24-hour minimum recorded at official stations, where even small differences in shower timing or boundary-layer mixing can shift the outcome by 1°C.