The Weather of February 2012

     With frequent interchange of the northeast monsoon and the humid maritime airstream over the south China coast, February 2012 was marked by gloomy and humid weather with a few foggy episodes in Hong Kong.  The total duration of bright sunshine in the month was 38.1 hours, only about 40 percent of the normal   and the monthly mean relative humidity was 85 percent, 5 percent above normal.

     The month was also cooler with less rainfall than usual.  The mean temperature of the month was 15.8 degrees, 1.0 degree below the normal figure of 16.8 degrees.  The total rainfall in the month was 29.5 millimetres, 24.9 millimetres below the normal figure of 54.4 millimetres.

     A ridge of high pressure over southern China brought generally fine weather to Hong Kong on the first day of the month.  Affected by a fresh easterly airstream, local weather became cloudy on 2 February.  A replenishment of the northeast monsoon reached the coastal areas of Guangdong on the morning of 3 February, bringing cool weather with light rain patches to the territory on 3 and 4 February.  With the moderation of the northeast monsoon, there were some sunny intervals the next day. 

     Affected by a maritime airstream, the weather became humid with a few rain patches and coastal fog on 6 February.  Meanwhile, a cold front formed over the northeastern part of Guangdong that night and crossed the coastal areas of Guangdong the next morning.  Affected by the intense northeast monsoon behind the cold front, local weather was cloudy and cold with rain patches from 7 to 11 February.  With the moderation of the northeast monsoon, there were sunny intervals on 12 February. 

     Under the influence of a maritime airstream, it was humid with mist and coastal fog from 13 to 15 February.  Meanwhile, a cold front crossed the coastal areas of Guangdong on the evening of 15 February.  Local temperatures started to fall progressively on 16 February after the passage of the cold front.  The northeast monsoon behind the cold front brought cold weather to the territory from 17 to 19 February.  While the northeast monsoon weakening slightly, the weather remained cloudy and cool for the following two days. 

     A rain band over the coastal areas of Guangdong together with a humid maritime airstream brought rainy and foggy weather to the territory on 22 and 23 February.  On 23 February, the visibility at Waglan Island stayed around 100 meters for the whole day and the daily mean relative humidity at the Observatory was 99 percent, the record high since 1961. 

     A cold front edged across the Pearl River Estuary on the morning of 24 February and the associated northeast monsoon brought cooler and foggy weather to Hong Kong on 24 and 25 February.  With the strengthening of the northeast monsoon, the weather became cold with rain and mist for the next three days.  The temperatures at the Observatory fell to a minimum of 9.8 degrees on the morning of 28 February, the lowest of the month.  Affected by a fresh to strong easterly airstream, the weather was windy and cool with light rain patches on the last day of the month.

    One tropical cyclone occurred 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 February are tabulated in Table 2.