Table 1. Number of Days with Signals in Hong Kong between 1971-2000
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
-
-
-
-
4.33
February
-
-
-
-
4.30
March
-
-
-
-
3.83
April
0.17
0.03
-
-
3.00
May
0.43
0.27
0.07
-
1.60
June
2.23
1.23
0.20
0.03
1.17
July
4.43
2.57
0.50
0.07
0.50
August
3.93
1.67
0.67
0.13
0.17
September
4.53
2.23
0.40
0.07
1.77
October
3.17
2.03
0.20
0.07
5.30
November
0.50
0.17
0.07
-
4.83
December
0.07
0.07
-
-
5.23
Year
19.46
10.27
2.11
0.37
36.03
Table 2. Monthly Rainfall in Hong Kong between 1971-2000
Month
Total (mm)
Duration (hours)
Number of Days with
0.1 mm or more
25 mm or more
50 mm or more
January
24.9
43
5.60
0.20
0.00
February
52.3
76
9.47
0.53
0.07
March
71.4
91
10.47
0.67
0.30
April
188.5
87
11.67
2.57
1.23
May
329.5
101
15.47
3.77
2.00
June
388.1
95
18.77
4.17
2.13
July
374.4
80
17.77
4.67
2.40
August
444.6
87
17.43
5.40
2.40
September
287.5
68
14.80
3.47
1.60
October
151.9
50
8.10
1.57
1.00
November
35.1
36
5.67
0.37
0.10
December
34.5
36
4.27
0.30
0.13
Year
2382.7
850
139.49
27.69
13.36
Table 3. Thunderstorm Activity and Fog Observed
at the Observatory between 1971-2000
Month
Number of Days with Lightning
Number of Days with Thunderstorm
Number of Days with Fog (Visibility < 1000 m)
January
0.13
0.10
0.23
February
1.00
0.97
1.23
March
1.77
1.63
2.30
April
4.77
4.20
1.13
May
6.67
5.27
0.17
June
7.70
5.60
-
July
8.47
5.90
-
August
11.00
8.10
-
September
6.93
4.30
-
October
1.13
0.80
-
November
0.23
0.23
-
December
-
-
0.03
Year
49.80
37.10
5.09
Table 4. Monthly Air Temperature Recorded at the Observatory between
1971-2000
Month
Mean Daily Maximum (deg. C)
Mean (deg. C)
Mean Daily Minimum (deg. C)
January
18.6
16.1
14.1
February
18.6
16.3
14.4
March
21.5
18.9
16.9
April
25.1
22.5
20.6
May
28.4
25.8
23.9
June
30.4
27.9
26.1
July
31.3
28.7
26.7
August
31.1
28.4
26.4
September
30.2
27.6
25.6
October
27.7
25.3
23.4
November
24.0
21.4
19.4
December
20.3
17.8
15.7
Year
25.6
23.1
21.1
Table 5. Monthly Relative Humidity, Dew Point Temperature, Wet-bulb
Temperature and Vapour Pressure Recorded at the Observatory between 1971-2000
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
73
78
65
11.0
13.5
13.7
February
78
82
71
12.2
14.4
14.8
March
82
86
75
15.5
17.0
18.2
April
83
88
76
19.4
20.5
22.9
May
84
88
77
22.7
23.7
27.8
June
82
86
76
24.5
25.6
30.9
July
81
85
74
25.0
26.1
31.7
August
82
86
75
24.9
25.9
31.5
September
79
83
72
23.4
24.7
28.9
October
74
78
66
19.9
21.9
23.8
November
70
75
61
15.3
17.9
18.1
December
69
74
60
11.6
14.5
14.4
Year
78
82
71
18.8
20.5
23.1
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 1971-2000
Month
Cloud Amount (%)
Bright Sunshine
Mean Daily Global Solar Radiation (MJ/m2)
Duration (hours)
Percentage of Possible
January
60
141.7
42
10.55
February
73
93.8
29
9.61
March
79
89.6
24
10.18
April
80
101.8
27
11.83
May
77
138.6
34
14.35
June
76
158.3
39
15.31
July
68
214.9
52
17.52
August
69
189.7
48
16.07
September
65
171.8
47
15.14
October
57
191.1
53
14.46
November
53
178.2
54
12.64
December
51
173.3
52
11.13
Year
67
1842.9
41
13.23
Table 7. Monthly Prevailing Wind Direction and Mean Wind Speed
Recorded at the Observatory and Waglan Island between 1971-2000
Month
Observatory
Waglan Island
Prevailing Direction (deg.)
Mean Wind Speed (km/h)
Prevailing Direction (deg.)
Mean Wind Speed (km/h)
January
090
11.0
070
25.4
February
090
12.1
070
25.1
March
090
12.6
070
23.5
April
090
11.7
070
21.2
May
090
10.8
080
20.2
June
090
11.0
230
23.3
July
090
10.9
230
21.9
August
090
10.2
240
20.0
September
090
11.0
090
22.8
October
090
12.4
080
28.7
November
090
10.9
080
27.9
December
090
10.3
070
26.5
Year
090
11.2
070
23.9
Table 8. Monthly Atmospheric Pressure Recorded at the
Observatory between 1971-2000
Month
Mean (hPa)
Mean Diurnal Range (hPa)
January
1020.1
4.1
February
1018.6
4.2
March
1016.1
4.2
April
1012.8
3.9
May
1009.4
3.4
June
1006.2
3.2
July
1005.5
3.4
August
1005.1
3.5
September
1009.2
3.5
October
1014.0
3.6
November
1018.0
3.8
December
1020.5
4.0
Year
1013.0
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 1971-2000
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
17.5
17.7
80.7
57.9
February
16.7
17.0
16.6
16.7
67.6
53.0
March
17.9
18.2
17.6
17.8
78.1
63.5
April
20.9
21.3
20.7
20.9
93.2
80.0
May
24.5
25.0
24.5
24.7
118.4
98.3
June
26.5
26.9
26.6
26.9
129.0
112.7
July
26.6
27.1
27.2
27.5
155.5
131.6
August
26.5
27.0
27.1
27.4
143.2
120.9
September
27.1
27.5
27.5
27.7
134.2
99.0
October
26.3
26.6
26.4
26.6
136.4
92.8
November
23.4
23.6
23.3
23.5
112.5
74.0
December
19.8
20.0
19.7
19.9
94.5
60.8
Year
22.8
23.2
22.9
23.1
1343.4
1044.5
* 1975 - 2004
Table 10. Monthly Soil Temperature Recorded at the
Observatory between 1971-2000
