Table 1. Monthly mean numbers of days with tropical cyclone warning signals and Strong Monsoon Signal in
Hong Kong
between 1981-2010
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 |
- |
- |
- |
- |
4.00 |
February |
- |
- |
- |
- |
4.63 |
March |
- |
- |
- |
- |
4.43 |
April |
0.20 |
0.13 |
- |
- |
2.90 |
May |
0.40 |
0.23 |
0.07 |
- |
1.53 |
June |
1.80 |
0.93 |
0.20 |
0.03 |
1.27 |
July |
3.33 |
1.73 |
0.57 |
0.03 |
0.70 |
August |
3.83 |
1.50 |
0.57 |
0.10 |
0.27 |
September |
3.83 |
1.87 |
0.53 |
0.10 |
1.97 |
October |
2.00 |
1.03 |
0.07 |
- |
4.13 |
November |
0.40 |
0.07 |
- |
- |
4.77 |
December |
- |
- |
- |
- |
4.97 |
Year |
15.80 |
7.50 |
2.00 |
0.27 |
35.57 |
Figure 1.1. Monthly mean number of days with tropical cyclone warning signals in Hong Kong between 1981-2010
Figure 1.2. Monthly mean number of days with Strong Monsoon Signal in Hong Kong between 1981-2010
back to the top
Table 2. Monthly mean of rainfall in
Hong Kong
between 1981-2010
Month |
Total
(mm) |
Duration
(hours) |
Number of Days with |
0.1 mm
or more |
25 mm
or more |
50 mm
or more |
January |
24.7 |
46 |
5.37 |
0.23 |
0.00 |
February |
54.4 |
89 |
9.07 |
0.53 |
0.10 |
March |
82.2 |
101 |
10.90 |
0.87 |
0.37 |
April |
174.7 |
99 |
12.00 |
2.23 |
1.10 |
May |
304.7 |
106 |
14.67 |
3.97 |
1.73 |
June |
456.1 |
111 |
19.07 |
5.27 |
2.60 |
July |
376.5 |
85 |
17.60 |
4.60 |
2.27 |
August |
432.2 |
97 |
16.93 |
5.37 |
2.47 |
September |
327.6 |
78 |
14.67 |
3.80 |
2.00 |
October |
100.9 |
46 |
7.43 |
1.20 |
0.70 |
November |
37.6 |
38 |
5.47 |
0.43 |
0.13 |
December |
26.8 |
40 |
4.47 |
0.20 |
0.07 |
Year |
2398.5 |
935 |
137.63 |
28.70 |
13.53 |
Figure 2. Monthly mean of rainfall in Hong Kong between 1981-2010
back to the top
Table 3. Monthly mean numbers of days with lightning,thunderstorm and fog reported at the Observatory between 1981-2010
Month |
Number of Days with
Lightning |
Number of Days with
Thunderstorm |
Number of Days with Fog
(Visibility < 1000 m) |
January |
0.13 |
0.13 |
0.30 |
February |
0.90 |
0.87 |
1.20 |
March |
1.90 |
1.77 |
2.00 |
April |
4.13 |
3.50 |
1.03 |
May |
6.77 |
5.20 |
0.07 |
June |
9.07 |
7.03 |
- |
July |
9.77 |
6.60 |
- |
August |
11.23 |
8.33 |
- |
September |
7.13 |
4.40 |
- |
October |
0.97 |
0.53 |
- |
November |
0.27 |
0.23 |
- |
December |
0.03 |
- |
0.03 |
Year |
52.30 |
38.60 |
4.63 |
Figure 3. Monthly mean numbers of days with lightning, thunderstorm and fog reported at the Observatory between 1981-2010
back to the top
Table 4. Monthly means of daily maximum, mean and minimum temperature recorded at the Observatory between 1981-2010
Month |
Mean Daily
Maximum
(deg. C) |
Mean
(deg. C) |
Mean Daily
Minimum
(deg. C) |
January |
18.6 |
16.3 |
14.5 |
February |
18.9 |
16.8 |
15.0 |
March |
21.4 |
19.1 |
17.2 |
April |
25.0 |
22.6 |
20.8 |
May |
28.4 |
25.9 |
24.1 |
June |
30.2 |
27.9 |
26.2 |
July |
31.4 |
28.8 |
26.8 |
August |
31.1 |
28.6 |
26.6 |
September |
30.1 |
27.7 |
25.8 |
October |
27.8 |
25.5 |
23.7 |
November |
24.1 |
21.8 |
19.8 |
December |
20.2 |
17.9 |
15.9 |
Year |
25.6 |
23.3 |
21.4 |
Figure 4. Monthly means of daily maximum, mean and minimum temperature recorded at the Observatory between 1981-2010
back to the top
Table 5. Monthly means of relative humidity, dew point temperature, wet-bulb temperature and vapour pressure recorded at the Observatory between 1981-2010
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 |
74 |
78 |
66 |
11.4 |
13.8 |
14.0 |
February |
80 |
83 |
73 |
13.0 |
14.7 |
15.5 |
March |
82 |
85 |
75 |
15.7 |
17.2 |
18.4 |
April |
83 |
87 |
77 |
19.4 |
20.6 |
23.0 |
May |
83 |
87 |
76 |
22.6 |
23.7 |
27.7 |
June |
82 |
86 |
77 |
24.6 |
25.6 |
31.0 |
July |
81 |
85 |
74 |
25.1 |
26.1 |
31.8 |
August |
81 |
85 |
74 |
25.0 |
26.0 |
31.7 |
September |
78 |
83 |
72 |
23.4 |
24.8 |
29.0 |
October |
73 |
78 |
66 |
20.2 |
22.1 |
24.1 |
November |
71 |
76 |
63 |
16.0 |
18.4 |
18.8 |
December |
69 |
74 |
61 |
11.9 |
14.8 |
14.6 |
Year |
78 |
82 |
71 |
19.0 |
20.6 |
23.3 |
Figure 5.1. Monthly mean of relative humidity recorded at the Observatory between 1981-2010
Figure 5.2. Monthly means of dew point temperature, web-bulb temperature and vapour pressure recorded at the Observatory between 1981-2010
back to the top
Table 6. Monthly means of cloud amount observed at the Observatory and sunshine duration and daily global solar radiation recorded at King's Park between 1981-2010
Month |
Cloud Amount
(%) |
Bright Sunshine |
Daily Global
Solar Radiation
(MJ/m2) |
Duration
(hours) |
Percentage
of Possible |
January |
61 |
143.0 |
42 |
10.17 |
February |
74 |
94.2 |
29 |
9.39 |
March |
79 |
90.8 |
24 |
9.96 |
April |
81 |
101.7 |
27 |
11.60 |
May |
76 |
140.4 |
34 |
14.19 |
June |
77 |
146.1 |
36 |
14.19 |
July |
69 |
212.0 |
51 |
17.17 |
August |
69 |
188.9 |
47 |
15.63 |
September |
66 |
172.3 |
47 |
14.61 |
October |
58 |
193.9 |
54 |
14.05 |
November |
54 |
180.1 |
54 |
12.28 |
December |
52 |
172.2 |
51 |
10.89 |
Year |
68 |
1835.6 |
42 |
12.85 |
Figure 6.1. Monthly mean of cloud amount recorded at the Observatory between 1981-2010
Figure 6.2. Monthly mean of sunshine duration recorded at King's Park between 1981-2010
Figure 6.3. Monthly mean of daily global solar radiation recorded at King's Park between 1981-2010
back to the top
Table 7. Monthly means of prevailing wind direction and mean wind speed recorded at the Observatory and Waglan Island between
1981-2010
Month |
Observatory |
Waglan Island |
Prevailing Wind
Direction
(deg.) |
Mean Wind
Speed (km/h) |
Prevailing Wind
Direction
(deg.) |
Mean Wind
Speed (km/h) |
January |
090 |
10.6 |
060 |
25.3 |
February |
090 |
11.7 |
070 |
24.5 |
March |
090 |
12.0 |
060 |
23.0 |
April |
090 |
11.5 |
070 |
20.9 |
May |
090 |
10.7 |
080 |
19.7 |
June |
090 |
10.6 |
220 |
22.9 |
July |
260 |
10.7 |
230 |
21.3 |
August |
090 |
10.2 |
230 |
19.4 |
September |
090 |
11.4 |
090 |
22.6 |
October |
090 |
12.1 |
080 |
27.4 |
November |
090 |
11.0 |
080 |
27.0 |
December |
090 |
10.0 |
070 |
26.0 |
Year |
090 |
11.0 |
080 |
23.3 |
Figure 7. Monthly means of prevailing wind direction and mean wind speed recorded at the Observatory and Waglan Island between 1981-2010
back to the top
Table 8. Monthly mean of atmospheric pressure recorded at the Observatory between 1981-2010
Month |
Mean (hPa) |
Mean Diurnal
Range (hPa) |
January |
1020.3 |
4.1 |
February |
1018.5 |
4.2 |
March |
1016.0 |
4.3 |
April |
1012.9 |
3.9 |
May |
1009.3 |
3.5 |
June |
1006.1 |
3.2 |
July |
1005.7 |
3.4 |
August |
1005.2 |
3.5 |
September |
1008.9 |
3.6 |
October |
1014.1 |
3.6 |
November |
1017.7 |
3.9 |
December |
1020.5 |
4.1 |
Year |
1012.9 |
3.8 |
Figure8. Monthly mean of atmospheric pressure recorded at the Observatory between 1981-2010
back to the top
Table 9. Monthly means of sea surface temperature recorded at North Point and Waglan Island, and evaporation and potential evapotranspiration recorded at King's Park between 1981-2010
Month |
Sea Surface Temperature (deg. C) |
Evaporation
(mm) |
Potential
Evapotranspiration
(mm) |
North Point |
Waglan Island |
0700 hours |
1400 hours |
0700 or
1100 hours |
1400 or
1700 hours |
January |
17.4 |
17.7 |
17.6 |
17.7 |
71.3 |
61.2 |
February |
16.8 |
17.1 |
16.8 |
16.9 |
59.9 |
58.7 |
March |
18.0 |
18.3 |
18.0 |
18.2 |
70.5 |
65.3 |
April |
21.0 |
21.4 |
20.9 |
21.1 |
83.8 |
81.6 |
May |
24.5 |
25.0 |
24.6 |
24.8 |
110.7 |
101.8 |
June |
26.5 |
26.9 |
26.5 |
26.7 |
117.1 |
108.0 |
July |
26.6 |
27.1 |
26.9 |
27.2 |
146.2 |
125.9 |
August |
26.6 |
27.1 |
27.1 |
27.3 |
134.9 |
120.6 |
September |
27.1 |
27.5 |
27.4 |
27.7 |
125.9 |
100.3 |
October |
26.3 |
26.6 |
26.4 |
26.6 |
123.9 |
96.0 |
November |
23.4 |
23.7 |
23.3 |
23.5 |
99.5 |
78.8 |
December |
19.8 |
20.1 |
19.8 |
20.0 |
83.7 |
64.1 |
Year |
22.8 |
23.2 |
22.9 |
23.2 |
1227.3 |
1062.4 |
Figure9.1. Monthly means of sea surface temperature recorded at North Point and Waglan Island between 1981-2010
Figure9.2. Monthly means of evaporation and potential evapotranspiration recorded at King's Park between 1981-2010
back to the top
Table 10. Monthly mean of soil temperature recorded at the Observatory between 1981-2010
Month |
0.5 m |
1.0 m |
1.5 m |
0700 hours
(deg. C) |
1900 hours
(deg. C) |
0700 hours
(deg. C) |
1900 hours
(deg. C) |
0700 hours
(deg. C) |
1900 hours
(deg. C) |
January |
18.8 |
18.7 |
20.3 |
20.3 |
21.5 |
21.5 |
February |
19.0 |
18.9 |
19.9 |
19.9 |
20.7 |
20.7 |
March |
20.9 |
20.9 |
21.0 |
21.0 |
21.3 |
21.3 |
April |
23.5 |
23.5 |
22.9 |
23.0 |
22.6 |
22.7 |
May |
26.6 |
26.6 |
25.6 |
25.7 |
24.8 |
24.9 |
June |
28.5 |
28.5 |
27.6 |
27.7 |
26.9 |
26.9 |
July |
29.8 |
29.8 |
29.0 |
29.0 |
28.2 |
28.3 |
August |
30.0 |
29.9 |
29.4 |
29.4 |
28.9 |
28.9 |
September |
29.6 |
29.5 |
29.3 |
29.3 |
29.1 |
29.0 |
October |
27.8 |
27.7 |
28.1 |
28.1 |
28.2 |
28.2 |
November |
24.5 |
24.4 |
25.7 |
25.6 |
26.4 |
26.4 |
December |
21.0 |
21.0 |
22.8 |
22.8 |
24.1 |
24.1 |
Year |
25.0 |
25.0 |
25.1 |
25.2 |
25.2 |
25.2 |
Figure10. Monthly mean of soil temperature recorded at the Observatory between 1981-2010
back to the top