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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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Table 10.   Monthly Soil Temperature Recorded at the Observatory
between 1967-1996

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