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EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG,
MAY 2018 (Table 1)

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 1012.5 30.6 27.3 25.4 23.5 80 76 Trace
2 1012.4 31.8 27.9 25.6 23.0 75 64 -
3 1014.1 33.5 27.1 22.9 23.2 80 82 1.9
4 1016.1 25.1 23.8 22.1 20.6 82 89 0.8
5 1015.5 27.7 25.3 23.6 22.0 82 86 Trace
6 1011.3 31.0 27.6 25.4 23.7 80 80 1.0
7 1007.2 29.6 28.0 24.4 24.7 82 88 6.7
8 1008.3 27.1 25.2 23.7 23.5 91 88 28.4
9 1012.9 25.7 24.6 22.8 22.4 88 88 5.4
10 1015.0 23.9 23.0 22.2 21.1 89 90 8.0
11 1014.2 25.3 23.8 22.3 21.3 86 88 1.0
12 1012.3 30.6 26.5 24.2 23.1 82 71 -
13 1011.0 31.5 27.7 25.3 23.7 79 41 -
14 1010.0 31.9 28.6 26.6 24.1 77 43 -
15 1009.3 32.3 28.7 27.1 23.9 76 54 -
16 1008.8 32.2 28.6 26.1 23.5 74 46 -
17 1008.2 33.1 29.4 27.4 24.3 75 64 -
18 1007.7 33.4 29.8 27.7 24.4 74 73 -
19 1007.7 33.4 29.8 27.8 24.6 74 72 -
20 1008.4 34.5 30.1 27.8 24.2 72 41 -
21 1009.5 34.7 30.3 28.1 24.3 71 54 -
22 1010.5 34.8 30.4 27.9 24.0 69 28 -
23 1009.6 35.1 30.5 27.6 24.0 69 18 -
24 1009.3 33.5 30.0 28.4 24.5 73 46 -
25 1008.2 33.1 29.8 27.6 24.0 71 47 Trace
26 1008.3 34.7 30.7 28.8 24.9 72 49 0.9
27 1008.9 33.4 30.0 26.9 25.3 76 63 3.4
28 1009.0 34.5 30.3 27.8 24.3 72 47 -
29 1009.6 35.3 31.1 28.3 24.5 69 24 -
30 1009.7 35.4 31.2 29.0 24.6 69 60 -
31 1009.7 34.8 31.1 28.9 24.7 70 57 -
Mean/Total 1010.5 31.7 28.3 26.1 23.7 77 62 57.5
Normal* 1009.3 28.4 25.9 24.1 22.6 83 76 304.7
Station Hong   Kong   Observatory

EXTRACT OF METEOROLOGICAL OBSERVATIONS FOR HONG KONG,
MAY 2018 (Table 2)

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 6.0 17.40 3.8 080 6.0
2 0 10.4 26.16 5.8 230 15.7
3 5 7.0 17.66 5.2 080 26.5
4 0 0.8 7.94 1.8 070 38.0
5 0 4.2 16.39 3.1 060 24.7
6 0 7.8 23.01 5.7 210 17.3
7 0 2.6 13.09 5.8 200 34.3
8 0 0.1 6.40 1.4 020 12.5
9 0 0.1 2.28 1.6 080 41.2
10 0 0.4 5.27 1.0 080 51.6
11 0 0.2 11.12 2.0 070 34.0
12 0 8.1 21.06 3.6 050 10.2
13 0 11.1 27.31 5.7 230 15.1
14 0 10.8 27.79 6.3 230 18.6
15 0 7.4 19.81 5.1 150 14.5
16 0 10.6 25.02 4.2 150 12.6
17 0 9.5 25.68 5.8 200 16.5
18 0 10.3 25.56 6.2 220 16.9
19 0 11.3 26.52 6.6 230 16.6
20 0 11.3 27.86 6.7 220 16.0
21 0 9.4 24.37 6.2 190 8.2
22 0 8.3 18.76 5.3 180 11.0
23 0 11.8 25.32 5.4 220 16.2
24 0 5.5 16.62 4.4 150 12.3
25 0 8.4 21.54 5.2 190 15.8
26 0 10.9 26.92 6.2 220 23.5
27 0 9.7 24.08 6.0 230 23.7
28 4 10.4 25.05 6.3 260 16.9
29 0 12.2 27.79 6.8 250 21.5
30 0 8.4 25.28 6.4 230 19.4
31 0 11.9 27.78 4.0 230 20.2
Mean/Total 9 236.9 20.54 149.6 220 20.2
Normal* 45.4§ 140.4 14.19 110.7 080 19.7
StationHong   Kong
International   Airport
King's   Park Waglan   Island^

The minimum pressure recorded at the Hong Kong Observatory was 1004.2 hectopascals at 1603 HKT on 7 May.

The maximum air temperature recorded at the Hong Kong Observatory was 35.4 degrees C at 1402 HKT on 30 May.

The minimum air temperature recorded at the Hong Kong Observatory was 22.1 degrees C at 0323 HKT on 4 May.

The maximum gust peak speed recorded at Waglan Island was 75 kilometres per hour from 080 degrees at 1640 HKT on 9 May.

The maximum 1-minute mean rainfall rate recorded at King's Park was 63 millimetres per hour at 2359 HKT on 7 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.

* 1981-2010 Climatlogical Normal, unless otherwise specified

§ 1997-2017 Mean value

Last revision date: <04 Jun 2018>