Monthly Normals of Meteorological Elements for September 1981-2010,
with Extreme Values between 1884-1939 and 1947-2011 for Hong Kong
 

Meteorological Elements					Date on which extreme value was recorded
ATMOSPHERIC PRESSURE	Absolute Maximum		1018.2	hPa	26/9/1902
	Mean		1008.9	hPa
	Absolute Minimum		953.2	hPa	1/9/1962
	Mean Diurnal Range		3.6	hPa
AIR TEMPERATURE	Absolute Maximum		35.2	deg. C	5/9/1963
	Mean Daily Maximum		30.1	deg. C
	Mean		27.7	deg. C
	Mean Daily Minimum		25.8	deg. C
	Absolute Minimum		18.4	deg. C	26/9/1935
RELATIVE HUMIDITY	Mean		78	%
	Absolute Minimum		26	%	17/9/1966
AMOUNT OF CLOUD			66	%
RAINFALL	Total		327.6	mm
	Duration		78	hours
	Number of Days with	0.1 mm or above	14.67
		25.0 mm or above	3.80
		50.0 mm or above	2.00
	Maximum Hourly		84.0	mm	22/9/1948
	Maximum Daily		325.5	mm	27/9/1965
	Maximum Monthly		844.2	mm	1952
NUMBER OF DAYS WITH THUNDERSTORM			4.40
NUMBER OF DAYS WITH FOG (Visibility < 1000 m)			0
SOIL TEMPERATURE AT 0700 HOURS	0.5 m		29.6	deg. C
	1.0 m		29.3	deg. C
BRIGHT SUNSHINE AT KING'S PARK	Duration		172.3	hours
	Percentage of Possible		47	%
WIND AT WAGLAN ISLAND	Prevailing Direction		090	degrees
	Mean Speed		22.6	km/h
	Maximum Gust #		234	km/h	16/9/1999
SEA SURFACE TEMPERATURE AT NORTH POINT AT 0700 HOURS			27.1	deg. C

Note : All measurements were made at the Hong Kong Observatory except where specified.

 #  1953 - 2011