The Weather of February 2007

February 2007 was unseasonably warm. Both the monthly mean temperature of 19.5 degrees and the mean daily minimum temperature of 17.8 degrees were the highest on record for February. It was also sunnier and drier than usual. The total duration of bright sunshine was 129.6 hours, 31.9 hours above normal. Only 6.9 millimetres of rainfall were recorded during the month, about one seventh of the normal figure of 48.0 millimetres. The accumulated rainfall in the first two months of the year amounted to 36.5 millimetres, about half of the normal figure of 71.4 millimetres for the same period.

Under the influence of the northeast monsoon, it was sunny and dry on the first four days of the month. The weather remained generally fine and mild between 5 and 7 February with a ridge of high pressure dominating over southeastern China.

A maritime airstream brought warm and sunny weather to the territory on 8 and 9 February. The temperature rose up to 25.6 degrees on 9 February, the highest in the month.

The local weather turned cloudy on 10 and 11 February when a surge of the northeast monsoon arrived at the south China coast. Clouds thinned out on 12 February and there were sunny periods in the ensuing two days. It was also misty on 14 February with the visibility in the harbour falling below 3000 metres. A cold front moved across the south China coast on 15 February and brought some rain patches to the territory. The weather stayed cloudy with light rain the next day.

Under the influence of a maritime airstream, it was warm with fog patches on 17 and 18 February. The maximum temperature on 18 February reached 25.3 degrees, making it the warmest Lunar New Year's Day on record.

Another cold front arrived at the coast of Guangdong on 19 February, bringing some rain patches to Hong Kong. It was misty with some rain in the following three days.

The weather became fine on 23 February but rain patches returned on 24 February when local winds strengthened from the northeast. A trough of low pressure moved across the south China coast and brought some rain to the territory on the morning of 25 February. While it was cloudy on 26 February, the weather became mainly fine the next day.

It was cloudy on the last day of the month as the winds strengthened from the east.

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 1.2. Monthly meteorological figures and departures from normal for February are tabulated in Table 2.

Warnings and Signals issued in February 2007

Table 1.1 Strong Monsoon Signal

Beginning Time		Ending Time
Day/Month	HKT	Day/Month	HKT
15 / 2	1520	15 / 2	2045
24 / 2	0745	24 / 2	1330
28 / 2	0940	28 / 2	1845

Table 1.2 Fire Danger Warnings

Colour	Beginning Time		Ending Time
Colour	Day/Month	HKT	Day/Month	HKT
Red	30 / 1	1330	3 / 2	0600
Yellow	3 / 2	1100	5 / 2	0600
Yellow	5 / 2	1215	6 / 2	0600

Table 2 Figures and Departures from Normal - February 2007

Meteorological Element	Figure of the Month	Departure from Normal*
Mean Daily Maximum Air Temperature	21.9 degrees C	3.3 degrees above normal
Mean Air Temperature	19.5 degrees C	3.6 degrees above normal
Mean Daily Minimum Air Temperature	17.8 degrees C	3.9 degrees above normal
Mean Dew Point Temperature	15.5 degrees C	3.7 degrees above normal
Mean Relative Humidity	79 %	1 % above normal
Mean Cloud Amount	67 %	6 % below normal
Total Rainfall	6.9 mm	41.1 mm below normal
Number of hours of Reduced VisibilityΔ	194 hours	70.1 hours above normal§
Total Bright Sunshine Duration	129.6 hours	31.9 hours above normal
Mean Daily Global Solar Radiation	11.51 Megajoule / square metre	0.82 Megajoule above normal
Total Evaporation	64.1 mm	14.9 mm below normal

Remarks :	All measurements were made at the Hong Kong Observatory except sunshine, solar radiation and evaporation which were recorded at King's Park Meteorological Station and visibility which was observed at the Hong Kong International Airport.
Δ	The visibility readings at the Hong Kong International Airport are based on hourly observations by professional meteorological observers in 2004 and before, and average readings over the 10-minute period before the clock hour of the visibility meter near the middle of the south runway from 2005 onwards. The change of the data source in 2005 is an improvement of the visibility assessment using instrumented observations following the international trend. Before 10 October 2007, the number of hours of reduced visibility at the Hong Kong International Airport in 2005 and thereafter displayed in this web page was based on hourly visibility observations by professional meteorological observers. Since 10 October 2007, the data have been revised using the average visibility readings over the 10-minute period before the clock hour, as recorded by the visibility meter near the middle of the south runway.
	The calibration factors of the pyranometer at King's Park in 2006 and 2007 have been re-computed based on the results of a regional instrument comparison in Asia in 2007. The readings of total global solar radiation at King's Park in 2006 and 2007 displayed in this web page before 13 June 2008 have been revised on 13 June 2008 using the new calibration factors.
* Departure from 1961-1990 climatological normal, except for number of hours of reduced visibility.
§ Departure from mean value between 1997 and 2006.

daily values of selected meteorological elements for HK for February 2007

Extract of Meteorological Observations in Hong Kong for February 2007