**Strong El Niño conditions in the equatorial Pacific, now strengthening toward very strong levels, represent the dominant driver suppressing western North Pacific tropical cyclone activity and steering patterns that typically deliver much of Hong Kong’s September rainfall.** With the climatological mean at 321 mm (1991–2020), traders assign over 51% implied probability to totals below 275 mm, reflecting expectations of fewer landfalling or nearby systems amid the El Niño influence. Early-month activity from Tropical Cyclone Saudel in the northern South China Sea has already produced localized squally showers and modest accumulations, yet model consensus and the seasonal shift toward drier autumn monsoon flow support below-normal overall precipitation. High interannual variability tied to cyclone frequency and tracks introduces uncertainty, with Hong Kong Observatory updates and late-month cyclone monitoring as key near-term catalysts.