Table 1. Number of Days with Signals in Hong Kong between 1961-1990
Month
Number
of Days with Tropical Cyclone Warning Signal
Number of Days
with Strong Monsoon Signal
No. 1 and/or higher
No. 3 and/or higher
No. 8 and/or higher
No. 9 and/or No. 10
January
-
-
-
-
2.77
February
-
-
-
-
3.17
March
-
-
-
-
2.60
April
0.17
-
-
-
2.37
May
0.70
0.50
0.13
0.03
1.13
June
1.97
0.93
0.13
-
0.93
July
4.57
2.93
0.67
0.07
0.30
August
3.33
1.70
0.53
0.17
0.17
September
4.50
2.50
0.57
0.10
1.17
October
3.37
2.40
0.30
0.10
3.80
November
0.50
0.30
0.07
-
3.27
December
0.07
0.07
-
-
3.97
Year
19.17
11.33
2.40
0.47
25.63
Table 2. Monthly Rainfall in Hong Kong between 1961-1990
Month
Total (mm)
Duration (hours)
Number of Days with
0.1 mm or more
25 mm or more
50 mm or more
January
23.4
41
5.63
0.10
0.00
February
48.0
69
8.93
0.43
0.03
March
66.9
89
10.07
0.60
0.27
April
161.5
82
11.13
2.20
0.97
May
316.7
92
14.93
3.40
1.93
June
376.0
86
19.23
4.23
1.97
July
323.5
67
17.47
3.93
1.97
August
391.4
73
17.30
4.70
2.17
September
299.7
68
14.37
3.57
1.63
October
144.8
48
8.60
1.50
0.87
November
35.1
37
5.87
0.40
0.10
December
27.3
31
3.87
0.23
0.10
Year
2214.3
782
137.40
25.30
12.00
Table 3. Thunderstorm Activity and Fog Observed
at the Observatory between 1961-1990
Month
Number of Days with Lightning
Number of Days with Thunderstorm
Number of Days with Fog (Visibility < 1000 m)
January
0.17
0.10
0.43
February
0.63
0.60
1.27
March
1.93
1.83
2.37
April
4.40
4.00
1.67
May
6.30
4.80
0.13
June
7.27
5.20
-
July
7.10
5.03
-
August
10.17
6.93
-
September
6.67
3.93
-
October
1.23
0.87
-
November
0.17
0.17
-
December
-
-
-
Year
46.03
33.47
5.87
Table 4. Monthly Air Temperature Recorded at the Observatory between
1961-1990
Month
Mean Daily Maximum (deg. C)
Mean (deg. C)
Mean Daily Minimum (deg. C)
January
18.6
15.8
13.6
February
18.6
15.9
13.9
March
21.3
18.5
16.5
April
24.9
22.2
20.2
May
28.7
25.9
23.9
June
30.3
27.8
25.9
July
31.5
28.8
26.6
August
31.3
28.4
26.3
September
30.3
27.6
25.5
October
27.9
25.2
23.1
November
24.2
21.4
19.2
December
20.5
17.6
15.4
Year
25.7
23.0
20.9
Table 5. Monthly Relative Humidity, Dew Point Temperature, Wet-bulb
Temperature and Vapour Pressure Recorded at the Observatory between 1961-1990
Month
Relative Humidity (%)
Dew Point Temperature (deg. C)
Wet-bulb Temperature (deg. C)
Vapour Pressure (hPa)
Mean
Mean at 0200 hours
Mean at 1400 hours
January
71
76
62
10.2
13.0
13.1
February
78
82
70
11.8
13.8
14.5
March
81
85
73
15.0
16.5
17.6
April
83
88
75
19.0
20.2
22.4
May
83
87
76
22.6
23.7
27.7
June
82
86
76
24.4
25.4
30.7
July
80
85
73
24.9
26.0
31.6
August
81
86
74
24.8
25.9
31.4
September
78
83
71
23.3
24.6
28.8
October
73
78
66
19.8
21.8
23.6
November
69
74
61
15.2
17.9
18.0
December
68
73
59
11.2
14.3
14.1
Year
77
82
70
18.6
20.3
22.8
Table 6. Monthly Cloud Amount Observed at the
Observatory and Monthly Bright Sunshine and Mean Daily Global Solar Radiation
Recorded at King's Park between 1961-1990
Month
Cloud Amount (%)
Bright Sunshine
Mean Daily Global Solar Radiation (MJ/m2)
Duration (hours)
Percentage of Possible
January
58
152.4
45
11.63
February
73
97.7
30
10.69
March
76
96.4
26
11.24
April
78
108.9
29
13.14
May
74
153.8
38
16.12
June
75
161.1
40
16.55
July
65
231.1
56
19.15
August
66
207.0
52
17.61
September
63
181.7
49
16.49
October
56
195.0
54
15.46
November
53
181.5
55
13.39
December
49
181.5
54
12.03
Year
65
1948.1
44
14.46
Table 7. Monthly Prevailing Wind Direction and Mean Wind Speed
Recorded at the Observatory and Waglan Island between 1961-1990
Month
Observatory
Waglan Island
Prevailing Direction (deg.)
Mean Wind Speed (km/h)
Prevailing Direction (deg.)
Mean Wind Speed (km/h)
January
090
11.2
070
24.0
February
090
11.9
070
23.8
March
090
12.6
070
22.1
April
090
11.7
080
19.7
May
090
10.6
090
19.2
June
090
10.4
090
21.6
July
090
10.1
230
20.0
August
090
9.4
090
18.5
September
090
10.7
090
21.9
October
090
12.2
090
27.6
November
090
11.0
080
27.2
December
090
10.5
080
25.5
Year
090
11.0
080
22.6
Table 8. Monthly Atmospheric Pressure Recorded at the
Observatory between 1961-1990
Month
Mean (hPa)
Mean Diurnal Range (hPa)
January
1020.2
4.1
February
1018.7
4.1
March
1016.2
4.2
April
1013.1
3.8
May
1009.1
3.4
June
1006.0
3.0
July
1005.3
3.4
August
1005.1
3.5
September
1008.8
3.6
October
1014.0
3.6
November
1017.9
3.8
December
1020.2
4.0
Year
1012.9
3.7
Table 9. Monthly Sea Surface Temperature Recorded at
North Point and Waglan Island and Monthly Total Evaporation and Potential
Evapotranspiration Recorded at King's Park between 1961-1990
Month
Sea Surface Temperature (deg. C)
Total Evaporation (mm)
Total Potential Evapotranspiration (mm)
North Point *
Waglan Island
0700 hours
1400 hours
0700 or 1100 hours
1400 or 1700 hours
January
17.5
17.7
17.1
17.3
97.5
73.2
February
16.7
17.0
16.3
16.4
79.0
66.3
March
17.9
18.2
17.3
17.5
92.2
77.0
April
20.9
21.3
20.3
20.5
106.9
92.0
May
24.5
25.0
24.5
24.8
137.7
115.0
June
26.5
26.9
26.6
26.9
143.9
126.6
July
26.6
27.1
27.4
27.7
171.6
150.5
August
26.5
27.0
27.3
27.6
156.9
135.8
September
27.1
27.5
27.4
27.7
150.3
120.6
October
26.3
26.6
26.3
26.5
152.2
112.8
November
23.4
23.6
23.4
23.5
129.1
88.8
December
19.8
20.0
19.5
19.7
111.5
76.7
Year
22.8
23.2
22.8
23.0
1528.8
1235.0
* 1975 - 2004
Table 10. Monthly Soil Temperature Recorded at the
Observatory between 1967-1996
