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EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG, MAY 2011

EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG,
MAY 2011

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 1010.5 28.4 25.9 24.1 23.3 86 81 Trace
2 1009.5 29.8 26.8 25.1 23.7 83 83 Trace
3 1009.3 30.7 27.3 25.9 23.1 78 83 Trace
4 1010.5 26.7 24.7 23.1 22.0 85 86 0.7
5 1011.0 24.8 23.6 22.5 21.8 90 91 Trace
6 1009.7 30.2 26.5 23.8 23.5 84 76 Trace
7 1008.6 31.3 27.6 25.4 23.7 80 78 Trace
8 1008.5 29.5 26.9 25.5 23.7 83 82 -
9 1007.5 30.5 27.3 25.3 24.1 83 63 -
10 1006.5 32.9 28.5 26.2 23.7 76 64 Trace
11 1006.2 33.0 29.3 27.5 25.2 79 74 -
12 1007.7 32.5 29.5 27.7 25.3 79 75 0.2
13 1009.7 28.8 26.9 24.8 24.7 88 85 33.5
14 1012.4 28.1 25.0 23.4 23.4 91 89 14.5
15 1014.2 25.1 24.4 23.6 23.1 92 89 2.9
16 1012.7 28.7 25.5 23.5 23.8 91 91 7.5
17 1011.2 24.7 23.4 22.4 21.0 86 86 0.3
18 1010.0 28.9 24.7 22.1 18.5 70 63 Trace
19 1010.0 29.6 25.8 23.6 21.8 79 68 -
20 1008.3 30.6 27.0 24.6 23.5 82 70 -
21 1006.9 29.6 26.1 24.6 24.2 89 83 42.8
22 1005.9 26.8 25.2 23.2 24.2 94 90 69.8
23 1007.3 26.4 24.2 23.2 21.6 86 91 9.3
24 1009.4 24.7 22.5 19.8 19.6 84 88 4.9
25 1010.0 24.7 23.0 21.0 19.9 83 88 0.3
26 1009.1 29.6 25.5 22.7 19.0 67 59 -
27 1007.1 30.0 26.7 24.2 20.7 70 56 -
28 1006.5 30.2 27.4 24.5 19.9 65 23 -
29 1010.6 29.4 26.9 25.3 22.8 79 51 -
30 1011.6 29.7 25.8 23.7 19.7 70 28 -
31 1007.4 32.5 26.7 23.3 19.7 67 42 -
Mean/Total 1009.2 29.0 26.0 24.1 22.4 81 73 186.7
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 1.1 11.32 2.5 160 9.1
2 0 3.9 17.03 4.9 160 12.9
3 0 3.8 15.59 3.7 170 11.8
4 3 2.4 13.48 3.2 040 16.8
5 1 0.2 8.99 2.9 050 19.2
6 5 4.2 15.43 4.3 180 14.3
7 0 6.5 19.85 4.5 140 11.3
8 0 7.2 19.45 4.7 110 14.0
9 0 7.9 20.66 4.5 060 13.3
10 0 7.6 19.55 5.6 200 11.5
11 0 6.9 19.56 4.1 220 17.0
12 0 5.7 18.08 5.2 220 14.9
13 4 0.6 8.08 2.6 200 14.3
14 1 1.3 9.92 2.4 080 35.0
15 8 - 7.02 1.3 090 29.7
16 4 2.1 10.00 2.3 040 9.8
17 0 0.1 5.01 2.1 080 22.5
18 0 8.9 25.66 5.2 060 28.2
19 0 10.1 23.81 2.8 060 24.5
20 0 10.4 24.74 5.1 050 14.9
21 0 1.7 13.54 3.8 070 14.3
22 0 - 3.19 1.6 160 20.3
23 0 1.0 12.06 3.6 020 12.4
24 2 - 7.26 1.7 020 19.5
25 16 0.1 7.62 2.6 020 18.4
26 12 8.8 23.33 5.2 020 11.3
27 15 6.1 17.16 4.1 020 6.2
28 14 11.0 23.23 6.0 210 9.7
29 21 9.0 22.14 6.5 100 23.7
30 4 10.0 25.92 6.1 090 25.3
31 4 11.9 25.40 6.7 040 18.0
Mean/Total 114 150.5 15.94 121.8 050 16.9
Normal* 52.8§ 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 1003.6 hectopascals at 1558 HKT on 22 May.

The maximum air temperature recorded at the Hong Kong Observatory was 33.0 degrees C at 1322 HKT on 11 May.

The minimum air temperature recorded at the Hong Kong Observatory was 19.8 degrees C at 0637 HKT on 24 May.

The maximum gust peak speed recorded at Waglan Island was 67 kilometres per hour from 220 degrees at 1415 HKT on 22 May.

The maximum instantaneous rate of rainfall recorded at the Hong Kong Observatory was 174 millimetres per hour at 2132 HKT on 22 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

§ 1997-2010 Mean value