The Weather of October 2003

October 2003 was sunnier and much drier than normal. The total duration of bright sunshine of 223.7 hours was about 15 per cent above normal. The monthly rainfall of 48.6 millimetres was only about one-third of the normal figure of 144.8 millimetres. The accumulated rainfall since the beginning of the year of 1 891.8 millimetres was about 12 per cent below the normal figure of 2 151.9 millimetres for the same period.

Apart from a few isolated showers on 1 October, it was fine and sunny in the first three days of the month. The temperature rose to 29.8 degrees on 2 October, the highest in the month. A weak cold front crossed the coast of South China on 4 October and brought slightly cooler weather to Hong Kong. The dry air behind the cold front maintained generally fine weather in Hong Kong for the next 4 days. Under light winds conditions, it was hazy on 8 and 9 October.

Clouds associated with an area of low pressure over the South China Sea drifted in on 10 October, bringing rainy weather to Hong Kong for two days. The rain became heavier on the evening of 10 October as winds strengthened from the east. There were also reports of thunderstorms in the afternoon the next day.

The weather improved briefly on 12 and 13 October. The mainly fine weather gave way to overcast conditions on 14 October as a cold front crossed the coast of South China. It became cooler in the next couple of days. The temperature fell to 19.9 degrees on the morning of 15 October, the lowest in the month.

The dry continental air associated with the northeast monsoon cleared the clouds on 16 October. Fine and dry weather prevailed throughout the rest of the month. During the period, the Red Fire Danger Warning was issued on 9 days. Haze was occasionally reported in the western part of the territory under light wind conditions.

A total of 3 tropical cyclones occurred in 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 1.3. Monthly meteorological figures and departures from normal for October are tabulated in Table 2.

Warnings and Signals issued in October 2003

Table 1.1 Strong Monsoon Signal

Beginning Time		Ending Time
Day/Month	HKT	Day/Month	HKT
11 / 10	0330	11 / 10	0815
14 / 10	0715	14 / 10	1145

Table 1.2 Thunderstorm Warning

Beginning Time		Ending Time
Day/Month	HKT	Day/Month	HKT
11 / 10	1025	11 / 10	1225
11 / 10	1400	11 / 10	1700
13 / 10	1530	13 / 10	1720

Table 1.3 Fire Danger Warnings

Colour	Beginning Time		Ending Time
Colour	Day/Month	HKT	Day/Month	HKT
Yellow	1 / 10	0600	1 / 10	1800
Yellow	4 / 10	0600	5 / 10	1800
Red	16 / 10	1200	18 / 10	0600
Yellow	18 / 10	0600	19 / 10	1800
Red	25 / 10	1100	27 / 10	0600
Red	29 / 10	0600	31 / 10	0600

Table 2 Figures and Departures from Normal - October 2003

Meteorological Element	Figure of the Month	Departure from Normal
Mean Daily Maximum Air Temperature	27.1 degrees C	0.8 degree below normal
Mean Air Temperature	25.3 degrees C	0.1 degree above normal
Mean Daily Minimum Air Temperature	23.6 degrees C	0.5 degree above normal
Mean Dew Point Temperature	19.6 degrees C	0.2 degree below normal
Mean Relative Humidity	71 %	2 % below normal
Mean Cloud Amount	44 %	12 % below normal
Total Rainfall	48.6 mm	96.2 mm below normal
Total Bright Sunshine Duration	223.7 hours	28.7 hours above normal
Mean Daily Global Solar Radiation	14.76 Megajoule / square metre	0.70 Megajoule below normal
Total Evaporation	119.8 mm	32.4 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.

daily values of selected meteorological elements for HK for October 2003

Extract of Meteorological Observations in Hong Kong for October 2003