Climate of Hong Kong

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The climate of Hong Kong is a monsoon-influenced humid subtropical climate (Köppen climate classification Cwa), just short of being a tropical wet-and-dry climate.

The Four Seasons in Hong Kong

In the winter, the weather is generally cool by local standards, with temperatures hovering between 15°C and 20°C. However, northeast winter monsoons bring frequent cold fronts which can cause the temperature to dip below 10°C, despite Hong Kong's tropical latitude and coastal location. Conversely, warm maritime airstreams also commonly raise the temperature well above 20°C. Temperatures as high as 29°C have been recorded in February. Winter starts sunny in December and becomes cloudier towards February.

Spring brings warmer and more humid weather. There is a sharp increase in rainfall around April. Spring is the cloudiest time of the year, with March and April both averaging only around 100 hours of bright sunshine.

Summer weather is hot, humid and unstable. Thunderstorms and brief showers are common, as well as sunny conditions. August has the highest average rainfall of any month. Temperatures usually exceed 30°C during the day, which, coupled with a high humidity, can result in an extreme heat index. Extreme heat indices are also caused by continuous sunshine and low breeze, usually last long around July and August, is a result in subtropical high pressure areas. This also occurs before typhoons hitting Hong Kong or nearby regions in the northeast, e.g. Taiwan or Eastern Coast of China, such outbound airstream bring even hotter weather, in addition to dirtier air. Nights are also warm with an average minimum temperature of 26°C. Hong Kong is frequently hit by typhoons in summer.

Autumn is generally considered as the most pleasant season. Temperatures are still high (20-27°C) while humidity and rainfall are considerably lower. Moreover, autumn is the sunniest season in Hong Kong, with October and November both averaging close to 200 hours of bright sunshine.

Hong Kong
Climate chart (explanation)
J F M A M J J A S O N D     25   19 14     52   19 14     71   22 17     189   25 21     330   28 24     388   30 26     374   31 27     445   31 26     288   30 26     152   28 23     35   24 19     35   20 16 Average max. and min. temperatures in °C Precipitation totals in mm Source: HKO
Imperial conversion J F M A M J J A S O N D     1   65 57     2.1   65 58     2.8   71 62     7.4   77 69     13   83 75     15   87 79     15   88 80     18   88 80     11   86 78     6   82 74     1.4   75 67     1.4   69 60 Average max. and min. temperatures in °F Precipitation totals in inches

	Winter	Spring	Summer	Autumn
Temperature	Mild (10 °C / 50 °F-23 °C / 73 °F)	Warm (17 °C / 62.6 °F-30 °C / 86.0 °F)	Generally hot days (30 °C / 86 °F-35 °C / 95 °F) and warm nights (25 °C / 77 °F-30 °C / 86 °F)	Warm (17 °C / 63 °F-30 °C / 86 °F)
Pressure	High pressure over central Asia grows stronger and forms anticyclone Cold front establishes	Anticyclone over central Asia weakens Low pressure begins to establish Troughs of low pressure develop over China	Low pressure well formed over central Asia Troughs of low pressure and typhoons affect Hong Kong	Low pressure over central Asia weakens Ridges of high pressure start to develop over central Asia
Relative Humidity	Relative humidity is fairly low but it fluctuates as dry, cool air from Mainland China alternates with warm, moist air from East China Sea over Hong Kong	Relative humidity begins to rise.	Relative humidity is very high and could reach over 80%.	Relative humidity starts to fall.
Precipitation and Condensation	Occasional light rains (caused by depressions passing over Mainland China). Frost may appear at the higher elevations.	Troughs of low pressure cause mists and advection fog over Hong Kong. Clouds sometimes develop and give light rainfall.	Heavy convection rain Violent thunderstorms fairly common. Typhoons sometimes pass through or nearby	Clouds and rainfall decrease. Cloudless sky becomes more common.
Wind	Dry, cool, and strong north-easterlies blow from Mainland China	Warm, light southerlies occasionally alternate with cold, dry north-easterlines	Warm, moist southerlies blow from the sea	Winds become cooler, dries, and easterly
Summary	Weather condition generally stable, but anticyclones and cold fronts bring changeable weather at times.	Conditions are warm and moist when the winds are southerly. Occasionally bursts of cold winds bring dry, cool weather. Generally, conditions become more unstable.	Changeable weather brought by tropical cyclones and thunderstorms. Weather conditions are generally unstable.	Conditions become more stable and pleasant.

Statistics

Climate data for Hong Kong
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Average high °C (°F)	18.6 (65.5)	18.6 (65.5)	21.5 (70.7)	25.1 (77.2)	28.4 (83.1)	30.4 (86.7)	31.3 (88.3)	31.1 (88.0)	30.2 (86.4)	27.7 (81.9)	24.0 (75.2)	20.3 (68.5)	25.6
Daily mean °C (°F)	16.1 (61.0)	16.3 (61.3)	18.9 (66.0)	22.5 (72.5)	25.8 (78.4)	27.9 (82.2)	28.7 (83.7)	28.4 (83.1)	27.6 (81.7)	25.3 (77.5)	21.4 (70.5)	17.8 (64.0)	23.1
Average low °C (°F)	14.1 (57.4)	14.4 (57.9)	16.9 (62.4)	20.6 (69.1)	23.9 (75.0)	26.1 (79.0)	26.7 (80.1)	26.4 (79.5)	25.6 (78.1)	23.4 (74.1)	19.4 (66.9)	15.7 (60.3)	21.1
Rainfall mm (inches)	24.9 (0.98)	52.3 (2.059)	71.4 (2.811)	188.5 (7.421)	329.5 (12.972)	388.1 (15.28)	374.4 (14.74)	444.6 (17.504)	287.5 (11.319)	151.9 (5.98)	35.1 (1.382)	34.5 (1.358)	2,382.7 (93.807)
% humidity	73	78	82	83	84	82	81	82	79	74	70	69	78.1
Avg. rainy days (≥ 0.1 mm)	5.60	9.47	10.47	11.67	15.47	18.77	17.77	17.43	14.80	8.10	5.67	4.27	139.49
Sunshine hours	141.7	93.8	89.6	101.8	138.6	158.3	214.9	189.7	171.8	191.1	178.2	173.3	1,842.9
Source: Hong Kong Observatory [1]

Climate of the past decade

1997. The year 1997 was the wettest year since records began in 1884. Rainfall at the Hong Kong Observatory amounted to 3,343.0 millimetres (131.61 in), 51 per cent above normal and exceeding the previous record set in 1982.

1998. It was the warmest year since records began in 1884. The annual mean temperature was 24.0 °C (75.2 °F), 0.2 °C (0.4 °F) higher than the previous record set in 1966. The annual mean daily minimum temperature of 22.1 °C (71.8 °F) was also the highest on record.

1999. With an annual mean temperature of 23.8 °C (74.8 °F), 1999 was the third warmest year on record. The monthly mean temperatures for all months except May, August and December were above their respective normal figures.

2000. The year 2000 was warmer and wetter than usual. The mean temperature of 23.3 °C (73.9 °F) was the tenth highest on record and the mean minimum temperature of 21.5 °C (70.7 °F) was the sixth highest. The annual total rainfall of 2,752.3 millimetres (108.36 in) was 24 per cent above normal.

2001. The year 2001 was warmer and wetter than usual. The mean temperature of 23.6 °C (74.5 °F) was 0.6 °C (1.1 °F) above normal, ranking the sixth highest on record. The mean minimum temperature of 21.8 °C (71.2 °F) was the second highest on record. The annual total rainfall of 3,091.8 millimetres (121.72 in) also ranked the fourth highest.

2002. The year 2002 was the second warmest year on record. The mean temperature of 23.9 °C (75.0 °F) was 0.9 °C (1.6 °F) above normal.

2003. The year 2003 was the sixth warmest year since records began in 1884. The mean temperature, 23.6 °C (74.5 °F), was 0.6 °C (1.1 °F) above normal.

2004. Globally, the year 2004 was the fourth warmest year since instrumental temperature record began in 1861. In Hong Kong, 2004 was the ninth warmest year on record. The annual mean temperature was 23.4 °C (74.1 °F), 0.4 °C (0.7 °F) above normal.

2005. Locally in Hong Kong, 2005 was the third wettest year on record. The total rainfall of 3,214.5 millimetres (126.56 in) was 45.2 percent above normal.

2006. Globally, the year 2006 is the sixth warmest year on record. In Hong Kong, it was the eighth warmest year since record began in 1884. The annual mean temperature of 23.5 °C (74.3 °F) was 0.5 °C (0.9 °F) higher than normal.

2008. Hong Kong was lashed by a torrential storm on the morning of June 7 which dumped up to 300 mm (11.8 in) of rain including 145.5 mm (5.73 in) between 8am and 9am killing 2 people. The storm also caused traffic delays and dozens of flight delays.

See also

• Geography of Hong Kong
• Environment of Hong Kong
• Great Hong Kong Typhoon of 1937

References

1. ^ "Monthly Meteorological Normals for Hong Kong". Hong Kong Observatory. http://www.weather.gov.hk/cis/normal/1971_2000/normals_e.htm. Retrieved 1 February 2008. 

External links

• Hong Kong Observatory web site
• Hong Kong Underground Observatory web site
• The Climate Information site from HKO
• Explanation of Hong Kong's Typhoon Signal System

Coordinates: 22°11′N 114°08′E / 22.183°N 114.133°E / 22.183; 114.133