The Weather of August 2014

    The weather of August 2014 was hotter than usual due to prolonged spells of fine and sunny weather during the month.  The monthly mean temperature of 29.0 degrees was 0.4 degree higher than the normal figure of 28.6 degrees, while the monthly duration of bright sunshine of 212.0 hours was about 12 percent above the normal figure of 188.9 hours.  With two heavy rain episodes around mid-August, the month was also wetter than usual with a monthly rainfall amount of 548.2 millimetres, about 27 percent above the August normal of 432.2 millimetres.  The accumulated rainfall since 1 January was 2312.1 millimetres, about 21 percent above the normal of 1905.5 millimetres for the same period.

    The very hot weather at the end of July continued into the first day of August, with temperatures at the Hong Kong Observatory reaching a maximum of 34.6 degrees, the highest of the month.  A southwesterly airstream maintained generally hot weather with sunny periods and a few thundery showers in the next three days.  Under the influence of a trough of low pressure along the south China coast, local weather became cloudier and more showery with a few thunderstorms from 5 to 7 August.  With the weakening of the trough, the weather in Hong Kong turned generally fine from 8 to 9 August.

    Sunny periods and a few showers on 10 and 11 August were followed by outbreaks of heavy rain and thunderstorms on 12 and 13 August under the influence of enhanced southwest monsoon associated with a trough of low pressure over the south China coastal areas.  Around 270 millimetres of rainfall were recorded at the Observatory over these two days.  A waterspout was observed over the waters south of Ap Lei Chau in the evening on 12 August.  As the trough weakened and the southwest monsoon moderated, rain eased off with sunny intervals on 14 August.

    Local weather remained generally fine on 15 - 18 August before unsettled weather with squally thunderstorms returned on 19 and 20 August as another trough of low pressure approached from southern China.  Heavy rain over these two days brought over 130 millimetres of rainfall to the Observatory, and together with the downpour a week earlier, rainfall over the two heavy rain episodes amounted to 400 millimetres, more than 90 per cent of the normal for August.

    The weather stayed generally fine from 21 to 30 August apart from a cloudy and showery interlude on 27 and 28 August as an area of low pressure moved across the South China Sea.  During its passage, easterly winds freshened along the coast of Guangdong and brought some relief from the sunny and very hot weather that prevailed during the period, with daytime temperatures at the Observatory exceeding 33 degrees on 24 - 26 August and again on 29 - 30 August.  Affected by showery activities associated with a broad trough of low pressure over the South China Sea, the weather turned mainly cloudy with a few showers and isolated thunderstorms on the last day of the month.