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 and
Extreme Values between 1884-1939 and 1947-2006
Month
Total (mm)
Duration (hours)
Number of Days with
Maximum Hourly (mm)
Maximum Daily (mm)
Maximum Monthly (mm)
0.1 mm or more
25 mm or more
50 mm or more
January
23.4
41
5.63
0.10
0.00
21.8
99.8
214.3
February
48.0
69
8.93
0.43
0.03
31.9
86.1
241.0
March
66.9
89
10.07
0.60
0.27
52.5
130.0
428.0
April
161.5
82
11.13
2.20
0.97
92.4
190.2
547.7
May
316.7
92
14.93
3.40
1.93
109.9
520.6
1241.1
June
376.0
86
19.23
4.23
1.97
108.2
411.3
1083.6
July
323.5
67
17.47
3.93
1.97
115.1
534.1
1147.2
August
391.4
73
17.30
4.70
2.17
82.1
334.2
1090.1
September
299.7
68
14.37
3.57
1.63
84.0
325.5
844.2
October
144.8
48
8.60
1.50
0.87
71.6
292.2
718.4
November
35.1
37
5.87
0.40
0.10
44.2
149.2
224.2
December
27.3
31
3.87
0.23
0.10
51.7
177.3
206.9
Year
2214.3
782
137.40
25.30
12.00
115.1
534.1
1241.1
Date on which the extreme value was recorded
16 Jul 2006
19 Jul 1926
May 1889
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 and Extreme Values between 1884-1939 and 1947-2006
Month
Absolute Maximum (deg. C)
Mean Daily Maximum (deg. C)
Mean (deg. C)
Mean Daily Minimum (deg. C)
Absolute Minimum (deg. C)
January
26.9
18.6
15.8
13.6
0.0
February
27.8
18.6
15.9
13.9
2.4
March
30.1
21.3
18.5
16.5
4.8
April
33.4
24.9
22.2
20.2
9.9
May
35.5
28.7
25.9
23.9
15.4
June
35.6
30.3
27.8
25.9
19.2
July
35.7
31.5
28.8
26.6
21.7
August
36.1
31.3
28.4
26.3
21.6
September
35.2
30.3
27.6
25.5
18.4
October
34.3
27.9
25.2
23.1
13.5
November
31.8
24.2
21.4
19.2
6.5
December
28.7
20.5
17.6
15.4
4.3
Year
36.1
25.7
23.0
20.9
0.0
Date on which the extreme value was recorded
19 Aug 1900 18 Aug 1990
18 Jan 1893
Table 5. Monthly Relative Humidity, Dew Point, Wet-bulb
Temperature and Vapour Pressure Recorded at the Observatory between 1961-1990
and Extreme Values between 1884-1939 and 1947-2006
Month
Relative Humidity (%)
Dew Point (deg. C)
Wet-bulb Temperature (deg. C)
Vapour Pressure (hPa)
Mean
Mean at 0200 hours
Mean at 1400 hours
Absolute Minimum
January
71
76
62
10
10.2
13.0
13.1
February
78
82
70
13
11.8
13.8
14.5
March
81
85
73
16
15.0
16.5
17.6
April
83
88
75
22
19.0
20.2
22.4
May
83
87
76
23
22.6
23.7
27.7
June
82
86
76
29
24.4
25.4
30.7
July
80
85
73
43
24.9
26.0
31.6
August
81
86
74
41
24.8
25.9
31.4
September
78
83
71
26
23.3
24.6
28.8
October
73
78
66
21
19.8
21.8
23.6
November
69
74
61
17
15.2
17.9
18.0
December
68
73
59
14
11.2
14.3
14.1
Year
77
82
70
10
18.6
20.3
22.8
Date on which the extreme value was recorded
16 Jan 1959
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, Mean Wind Speed
and Maximum Gust Recorded at the Observatory and Waglan Island between 1961-1990
Month
Observatory
Waglan Island
Prevailing Direction (deg.)
Mean Wind Speed (km/h)
Maximum Gust (km/h)*
Prevailing Direction (deg.)
Mean Wind Speed (km/h)
Maximum Gust (km/h)#
January
090
11.2
96
070
24.0
103
February
090
11.9
103
070
23.8
110
March
090
12.6
108
070
22.1
103
April
090
11.7
106
080
19.7
135
May
090
10.6
166
090
19.2
140
June
090
10.4
191
090
21.6
194
July
090
10.1
151
230
20.0
158
August
090
9.4
224
090
18.5
209
September
090
10.7
259
090
21.9
234
October
090
12.2
175
090
27.6
184
November
090
11.0
155
080
27.2
175
December
090
10.5
104
080
25.5
108
Year
090
11.0
259
080
22.6
234
Date on which the extreme value was recorded
1 Sep 1962
16 Sep 1999
* 1911 - 1939 and April 1947 - 2006
# 1953 - 2006
Table 8. Monthly Atmospheric Pressure Recorded at the
Observatory between 1961-1990 and Extreme Values between 1884-1939 and 1947-2006
Month
Absolute Maximum (hPa)
Mean (hPa)
Absolute Minimum (hPa)
Mean Diurnal Range (hPa)
January
1035.4
1020.2
1003.1
4.1
February
1032.7
1018.7
998.3
4.1
March
1033.9
1016.2
1001.9
4.2
April
1028.4
1013.1
999.9
3.8
May
1020.2
1009.1
981.1
3.4
June
1014.7
1006.0
973.8
3.0
July
1014.8
1005.3
975.8
3.4
August
1016.3
1005.1
961.6
3.5
September
1018.2
1008.8
953.2
3.6
October
1024.5
1014.0
977.3
3.6
November
1033.2
1017.9
974.9
3.8
December
1033.5
1020.2
1004.6
4.0
Year
1035.4
1012.9
953.2
3.7
Date on which the extreme value was recorded
6 Jan 1903
1 Sep 1962
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