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Monthly Meteorological Normals and Extremes for Hong Kong

  1. Number of Days with Signals in Hong Kong between 1961-1990
  2. Monthly Rainfall in Hong Kong between 1961-1990 and Extreme Values between 1884-1939 and 1947-2006
  3. Thunderstorm Activity and Fog Observed at the Observatory between 1961-1990
  4. Monthly Air Temperature Recorded at the Observatory between 1961-1990 and Extreme Values between 1884-1939 and 1947-2006
  5. Monthly Relative Humidity, Dew Point, Web-bulb Temperature and Vapour Pressure Recorded at the Observatory between 1961-1990 and Extreme Values between 1884-1939 and 1947-2006
  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
  7. Monthly Prevailing Wind Direction, Mean Wind Speed and Maximum Gust Recorded at the Observatory and Waglan Island between 1961-1990
  8. Monthly Atmospheric Pressure Recorded at the Observatory between 1961-1990 and Extreme Values between 1884-1939 and 1947-2006
  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
  10. Monthly Soil Temperature Recorded at the Observatory between 1967-1996




Table 1.   Number of Days with Signals in Hong Kong between 1961-1990
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Month
Number of Days with
Tropical Cyclone Warning Signal
Number of Days with
Strong Monsoon Signal
blank space
No. 1 and/or
higher
blank space
No. 3 and/or
higher
blank space
No. 8 and/or
higher
blank space
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
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Month
blank space
Total
(mm)
blank space
Duration
(hours)
Number of Days with blank space
Maximum
Hourly
(mm)
blank space
Maximum
Daily
(mm)
blank space
Maximum
Monthly
(mm)
blank space
0.1 mm
or more
blank space
25 mm
or more
blank space
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
blank space
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
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Month
blank space
Absolute
Maximum
(deg. C)
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Mean Daily
Maximum
(deg. C)
blank space
Mean
(deg. C)
blank space
Mean Daily
Minimum
(deg. C)
blank space
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
blank space
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
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Month
blank space
Cloud Amount
(%)
Bright Sunshine blank space
Mean Daily Global
Solar Radiation
(MJ/m2)
blank space
Duration
(hours)
blank space
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
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Month
Observatory Waglan Island
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Prevailing
Direction
(deg.)
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Mean Wind
Speed (km/h)
blank space
Maximum
Gust (km/h)*
blank space
Prevailing
Direction
(deg.)
blank space
Mean Wind
Speed (km/h)
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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
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Month
blank space
Absolute
Maximum (hPa)
blank space
Mean (hPa)
blank space
Absolute
Minimum (hPa)
blank space
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
blank space
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
blank space
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 18.9 18.9 20.5 20.6 21.7 21.7
February 18.8 18.9 19.9 20.0 20.9 20.9
March 20.4 20.5 20.7 20.7 21.1 21.1
April 23.1 23.3 22.6 22.6 22.4 22.4
May 26.5 26.7 25.5 25.5 24.8 24.8
June 28.4 28.6 27.5 27.6 26.8 26.8
July 29.9 30.0 29.0 29.1 28.3 28.3
August 30.0 30.1 29.5 29.5 29.0 29.0
September 29.6 29.7 29.4 29.4 29.1 29.1
October 27.6 27.6 28.1 28.1 28.2 28.2
November 24.4 24.4 25.7 25.6 26.4 26.3
December 20.6 20.6 22.5 22.5 23.7 23.7
Year 24.9 24.9 25.1 25.1 25.2 25.2



Last revision date: <20 Dec 2012>