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EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG, DECEMBER 2009

EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG,
DECEMBER 2009

Date
DECEMBER
Mean
Pressure
(hPa)
Air   Temperature Mean
Dew Point
Temperature
(deg. C)
Mean
Relative
Humidity
(%)
Mean
Amount
of Cloud
(%)
Total
Rainfall
(mm)
Maximum
(deg. C)
Mean
(deg. C)
Minimum
(deg. C)
1 1021.5 21.9 19.0 16.8 14.2 74 26 -
2 1020.9 21.9 19.8 18.1 14.8 73 55 -
3 1021.3 19.7 17.4 15.1 9.5 60 11 -
4 1019.8 20.1 17.6 15.7 11.5 67 26 -
5 1019.7 20.1 17.3 14.8 8.7 58 16 -
6 1018.2 20.3 18.4 16.3 13.0 71 43 Trace
7 1017.7 19.1 17.9 16.8 15.4 85 84 5.5
8 1016.8 19.8 18.6 17.8 17.5 94 88 14.1
9 1015.6 20.4 19.7 18.7 18.2 91 88 0.4
10 1014.8 23.0 20.3 18.3 17.3 84 60 Trace
11 1016.6 24.0 21.0 19.4 18.2 84 64 Trace
12 1017.8 20.9 20.4 19.8 17.6 84 84 Trace
13 1017.9 22.9 20.6 19.1 17.5 83 44 -
14 1018.5 21.2 19.8 18.7 17.2 85 72 1.0
15 1018.1 20.6 19.0 15.8 17.1 89 84 9.6
16 1021.3 15.8 13.9 12.7 11.3 84 81 3.8
17 1023.4 14.1 12.9 11.5 8.6 75 85 Trace
18 1025.8 14.1 12.5 11.7 8.4 76 88 Trace
19 1027.8 15.3 13.3 11.5 7.2 67 86 -
20 1026.9 16.5 13.8 11.3 3.5 50 60 -
21 1026.0 17.1 14.7 12.9 5.8 55 78 -
22 1022.1 18.3 16.0 14.2 11.0 72 38 -
23 1019.1 20.7 18.0 16.1 13.7 76 82 -
24 1016.2 23.1 20.0 18.3 17.2 84 24 -
25 1015.3 22.4 19.9 18.0 16.6 81 48 -
26 1016.6 19.3 18.1 17.3 14.3 78 80 -
27 1016.8 18.6 15.7 10.6 13.4 86 83 3.1
28 1018.4 14.6 12.2 9.4 9.7 85 87 5.7
29 1015.1 16.9 15.5 13.8 14.2 92 88 3.5
30 1015.3 17.9 17.2 16.4 16.0 93 87 2.5
31 1018.2 17.1 16.2 15.5 13.3 84 86 1.0
Mean/Total 1019.3 19.3 17.3 15.6 13.3 78 65 50.2
Normal* 1020.5 20.3 17.8 15.7 11.6 69 51 34.5
Station Hong   Kong   Observatory

Date
DECEMBER
Number of hours
of Reduced
Visibility#
(hours)
Total
Bright
Sunshine
(hours)
Daily
Global Solar
Radiation
(MJ/m2)
Total
Evaporation
(mm)
Prevailing
Wind
Direction
(degrees)
Mean
Wind
Speed
(km/h)
1 24 9.5 15.17 2.8 010 20.4
2 22 6.2 11.09 3.4 060 23.8
3 21 9.5 15.42 3.1 360 30.5
4 18 8.9 14.24 3.0 010 17.7
5 10 9.7 15.93 3.1 360 22.8
6 11 9.0 15.00 2.6 080 35.3
7 1 - 1.89 0.1 050 45.2
8 3 0.1 3.90 0.3 030 35.5
9 7 - 2.49 0.6 010 19.3
10 14 6.8 13.67 2.1 360 7.7
11 8 8.0 15.95 3.1 030 19.9
12 6 0.1 4.49 1.7 050 27.9
13 18 8.0 14.69 2.9 040 11.8
14 4 2.1 8.44 1.9 070 33.4
15 0 0.2 5.32 1.4 060 32.2
16 0 - 2.83 1.7 360 30.0
17 7 - 3.97 1.6 360 28.1
18 0 - 4.25 1.6 360 26.4
19 3 0.8 6.86 1.9 010 26.1
20 0 7.6 14.14 4.0 010 23.3
21 0 4.6 11.37 2.0 010 25.0
22 11 9.3 15.71 2.5 060 25.1
23 7 5.1 11.29 1.5 040 24.7
24 6 9.4 15.63 2.3 030 10.7
25 2 7.1 12.57 2.6 010 5.5
26 24 0.9 6.45 1.8 070 35.3
27 13 - 3.07 0.6 080 36.8
28 8 - 5.14 0.6 030 24.3
29 8 - 2.77 0.1 040 30.6
30 0 - 3.44 0.9 030 22.0
31 10 1.6 6.47 2.3 070 44.0
Mean/Total 266 124.5 9.15 60.1 010 25.8
Normal* 250.6§ 173.3 11.13 94.5 070 26.5
Station Hong   Kong
International   Airport
King's   Park Waglan   Island^

The minimum pressure recorded at the Hong Kong Observatory was 1012.5 hectopascals at 1549 HKT on 29 December.

The maximum air temperature recorded at the Hong Kong Observatory was 24.0 degrees C at 1301 HKT on 11 December.

The minimum air temperature recorded at the Hong Kong Observatory was 9.4 degrees C at 0523 HKT on 28 December.

The maximum gust peak speed recorded at Waglan Island was 67 kilometres per hour from 050 degrees at 1834 HKT on 7 December.

The maximum instantaneous rate of rainfall recorded at King's Park was 29 millimetres per hour at 0815 HKT on 30 December.

# Reduced visibility refers to visibility below 8 kilometres when there is no fog, mist, or precipitation.

-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.

^ In case the data are not available from Waglan Island, observations of Cheung Chau or other nearby weather stations will be incorporated in computing the Prevailing Wind Direction and Mean Wind Speed.

* 1971-2000 Climatological Normal, unless otherwise specified

§ 1997-2008 Mean value