September's rainfall was 102.3mm, about one third the normal figure of 299.7mm, the Hong Kong Observatory says.

Accumulated rainfall for the year so far was 1,635.6mm, about 19% below the normal figure of 2,007.1mm.

A trough of low pressure over the south China coast brought showery weather to Hong Kong September 2 to 5. With the trough moving south into the South China Sea, there were sunny intervals the following day but the weather stayed mainly cloudy with isolated showers over the following four days.

With light winds it was hazy September 14 to 17 with visibility dropping below 3km in some places. Winds then strengthened from the north and it was mainly fine and dry over the next five days.

Humidity fell to about 40% September 18 and 19. The combined effect of the northeast monsoon and Tropical Storm Francisco over the South China Sea brought windy and rainy weather to Hong Kong September 23 to 25.