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EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG, MAY 2009

EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG,
MAY 2009

Date
MAY
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 1016.2 27.9 23.3 20.7 17.2 69 34 -
2 1015.1 28.0 23.7 21.2 16.2 63 16 -
3 1014.1 28.8 24.2 21.5 18.8 73 52 Trace
4 1014.0 28.4 23.6 21.4 19.6 79 80 0.3
5 1013.8 28.2 24.0 22.0 18.1 71 51 -
6 1012.3 27.9 23.5 22.0 18.0 72 53 -
7 1010.5 29.4 24.2 20.9 14.8 58 29 -
8 1010.9 28.7 24.3 21.7 18.2 70 42 -
9 1010.6 29.4 25.2 23.0 20.5 76 66 Trace
10 1010.6 28.6 25.4 24.0 22.0 82 88 Trace
11 1011.1 31.0 26.5 24.4 22.7 81 68 -
12 1010.7 31.3 27.0 24.6 22.7 78 53 -
13 1009.5 31.3 27.1 24.8 22.9 78 53 Trace
14 1011.7 29.8 26.0 24.6 21.7 77 63 Trace
15 1012.7 30.3 26.3 24.4 21.8 77 59 -
16 1012.4 28.2 25.8 24.3 22.4 82 75 0.1
17 1011.1 30.8 27.3 24.9 23.4 80 77 0.2
18 1009.6 31.9 28.5 26.3 23.4 75 74 -
19 1008.9 32.0 28.6 26.9 23.8 76 79 0.3
20 1008.1 30.2 27.6 23.5 23.3 78 88 10.9
21 1010.0 30.9 27.5 24.8 24.4 84 83 1.4
22 1010.3 29.7 27.7 26.3 24.4 82 85 2.3
23 1008.4 27.1 25.7 24.6 24.5 93 91 62.3
24 1008.2 26.4 25.5 24.4 24.5 94 93 61.2
25 1009.5 25.5 24.9 24.2 23.9 94 94 29.8
26 1008.6 26.5 25.3 23.6 24.2 94 86 20.2
27 1007.4 28.9 25.5 23.4 24.1 92 84 39.2
28 1009.2 24.9 23.5 22.7 21.2 87 88 11.5
29 1011.3 23.7 22.2 20.8 19.6 86 88 5.5
30 1010.3 29.5 25.3 21.9 16.4 59 81 -
31 1008.6 28.2 26.4 24.7 19.7 67 86 -
Mean/Total 1010.8 28.8 25.5 23.5 21.2 78 70 245.2
Normal* 1009.4 28.4 25.8 23.9 22.7 84 77 329.5
Station Hong   Kong   Observatory

Date
MAY
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 0 11.2 26.54 5.8 070 31.7
2 0 11.1 26.62 5.5 050 16.7
3 3 9.0 21.07 3.9 020 12.0
4 0 5.2 16.09 4.5 030 19.1
5 0 9.4 26.70 6.3 080 26.0
6 0 6.6 21.74 5.7 080 34.1
7 0 11.4 27.31 5.8 070 32.6
8 0 7.1 21.81 4.5 070 23.7
9 0 10.4 25.74 4.1 080 22.1
10 0 2.7 13.02 3.3 080 22.0
11 0 7.9 23.90 4.8 080 16.4
12 0 8.9 19.55 4.2 020 8.1
13 0 9.7 23.24 5.4 110 8.7
14 0 6.3 20.05 4.6 080 22.5
15 1 7.2 20.87 4.4 070 17.9
16 0 2.2 10.34 1.8 030 5.5
17 1 10.1 25.76 6.3 220 13.5
18 0 8.8 25.18 6.5 210 13.8
19 0 7.0 19.89 5.6 180 18.8
20 0 1.3 11.26 4.0 160 24.6
21 0 3.0 12.57 2.9 160 16.2
22 0 1.4 12.66 2.8 080 24.6
23 0 - 0.73 3.5 080 41.0
24 0 - 2.09 2.1 100 30.4
25 1 0.1 2.32 2.5 090 37.2
26 1 0.8 7.19 0.6 090 22.9
27 0 3.7 14.82 1.0 100 32.1
28 2 0.4 9.80 2.4 090 41.8
29 0 - 5.01 2.0 070 31.5
30 0 6.4 19.65 4.3 360 8.7
31 8 0.5 13.37 3.4 170 5.0
Mean/Total 17 169.8 17.00 124.5 080 22.0
Normal* 57.8§ 138.6 14.35 118.4 080 20.2
Station Hong   Kong
International   Airport
King's   Park Waglan   Island^

The minimum pressure recorded at the Hong Kong Observatory was 1006.1 hectopascals at 1528 HKT on 27 May.

The maximum air temperature recorded at the Hong Kong Observatory was 32.0 degrees C at 1311 HKT on 19 May.

The minimum air temperature recorded at the Hong Kong Observatory was 20.7 degrees C at 0608 HKT on 1 May.

The maximum gust peak speed recorded at Waglan Island was 85 kilometres per hour from 080 degrees at 1730 HKT on 23 May.

The maximum instantaneous rate of rainfall recorded at the Hong Kong Observatory was 195 millimetres per hour at 1947 HKT on 20 May.

# 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