The Weather of March 2009

    March 2009 was wetter and milder than usual. The total rainfall in the month was 120.7 millimetres, about 69 percent above the normal figure of 71.4 millimetres. The mean temperature was 19.7 degrees, 0.8 degrees above the normal figure of 18.9 degrees.

    Under the influence of the northeast monsoon, the weather was cloudy with a few light rain and mist patches in the first four days of the month.

    A cold front developed over the northern part of southern China and moved towards the coast of Guangdong on 5 March. Local weather was rainy and foggy on the morning of 5 March. Rain became heavy with a few squally thunderstorms on that afternoon. The cold front moved across the coastal areas of southern China on 6 March, bringing rainy and rather cool weather to Hong Kong. Hails were reported at Tsuen Wan, Tsing Yi and northern Lantau on that morning. Affected by the northeast monsoon behind the cold front, it remained cool with a few rain patches in the ensuing three days.

    Under the influence of a fresh to strong easterly airstream, local weather was cloudy and windy from 10 to 12 March. An intense cold front crossed the coastal areas of southern China on 13 March. Temperatures at the Hong Kong Observatory dropped appreciably from around 25 degrees in the afternoon to around 14 degrees before mid-night of that day. Under the influence of the dry northeast monsoon behind the cold front, local weather was fine, dry and cool on 14 and 15 March. It remained generally fine with temperatures rising gradually in the next three days.

    A maritime airstream brought cloudy and foggy weather to the territory from 19 to 23 March. Visibility fell to below 400 metres in the harbour on 20 March. With the strengthening of the northeast monsoon over southern China, local weather was windy with a few squally thunderstorms on 24 and 25 March. A moist easterly airstream brought rainy and misty weather to Hong Kong from 26 to 28 March.

    A weak cold front crossed the coast of Guangdong on 29 March, bringing slightly cooler weather and a few thunderstorms to Hong Kong. It was mainly cloudy for the last two days of the month.

    There was no tropical cyclone over the South China Sea and the western North Pacific in the month.

    Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.4.  Monthly meteorological figures and departures from normal for March are tabulated in Table 2.