What's the climate like in Hong Kong?

Due to its low latitude and proximity to the ocean, Hong Kong has a subtropical maritime monsoon climate, which is characterized by neither extreme heat in summer nor severe cold in winter. Because it is located in the southeast coast of the Asian continent and is deeply influenced by the monsoon, it has formed a remarkable feature of seasonal variation of weather in the middle of the year. The cooling effect of the mainland surface in winter and the heating effect in summer make the climate of Hong Kong distinct in four seasons and quite different. So there is heat in summer and sudden cooling in winter. At the same time, due to the influence of tropical and temperate weather, the weather in Hong Kong changes differently every day. The average temperature in the coldest month of 65438+ 10 is 15.2 12 degrees, and the average temperature in July in the hottest month is 27.9 12 degrees, which is above annual range 12.7 degrees. Hong Kong has obvious rainy season (summer) and dry season (winter). In addition, during most of the year, the weather in Hong Kong may change dramatically. This change is generally due to the change of upper-air circulation and wind direction caused by the great disparity between land and sea surface temperature, which often causes different air currents to appear alternately in Hong Kong. Severe weather changes, usually caused by the passage of tropical cyclones.

A year in Hong Kong can be divided into four distinct seasons, but the length of each season is different.

First, winter. 165438+ October to February is winter in Hong Kong. In this season, dry and cold northerly winds prevail in Hong Kong, with the lowest temperature in a year, of which 65438+ 10 is the coldest, with an average temperature of15.6c. The weather in early winter is generally sunny and dry, but with the decrease of monsoon thickness, the cloud cover gradually increases. After the arrival of the new year, the weather became gloomy and drizzling. There is a cold peak crossing this season, which makes the wind stronger and the temperature drops obviously. Sometimes, there are clouds, light rain or Mao Mao rain. There is little chance of heavy rain in winter in Hong Kong, but when the border is disturbed by high altitude, there will be moderate to long-term rainfall occasionally.

Second, spring. March and April are spring in Hong Kong. This is a transitional season, characterized by wet and foggy weather. At this time, the continental anticyclone weakened, and the cold wave from the north became inconspicuous and not dense. With the invasion of warm air in the south, the temperature rises gradually, which also causes the widespread distribution of clouds and low-level clouds, which are usually stable. By the end of spring, due to the rising sea temperature along the coast of South China, there was little fog, the low-level clouds gradually turned into cumulus clouds, and the rainfall also turned into showers.

Third, summer. It is a long and hot season from May to mid-September. Southerly winds prevail in Hong Kong in summer, and the temperature remains high. The average monthly temperature is above 25℃, and the absolute maximum monthly temperature is above 35℃. At this time, the summer monsoon is not obvious and is often interrupted by interference. Tropical cyclones sometimes affect Hong Kong, increasing the easterly component of the summer monsoon and bringing a lot of rainfall. In summer, the clouds are mainly cumulus-shaped, and the rainfall is mostly thunderstorms. The probability of showers is 3-4 hours after dawn, with the least at dusk.

Fourth, autumn. Late September to165438+1early October is a short autumn in Hong Kong. After September, the air pressure in Chinese mainland began to rise, the humid tropical maritime air mass gradually weakened and retreated, and the temperature and rainfall decreased one after another. 65438+ 10 In the middle of June, an obvious northeast monsoon formed, blowing easterly, the relative humidity dropped sharply, the cloud cover decreased, and the sunshine was bright, which was a month with more sunshine time throughout the year. The frequency and intensity of tropical cyclones decrease from the peak, and the rainfall is mostly local showers, but the rainfall is not large.

temperature

The average annual temperature in Hong Kong is 22.8 degrees Celsius. Due to the adjustment of the ocean, the average temperature in the coldest month of 65438+ 10 is 15.6℃, and the average temperature in July in the hottest month is 28.6℃. The absolute maximum temperature is only 36.65438 0℃, and the average daily temperature difference is only 5.2℃.

rain

The average annual precipitation in Hong Kong is 2246.4 mm, and the precipitation from May to September accounts for about 80% of the whole year. It is the highest from June to July, especially in June, with an average precipitation of 457.5 mm ... 65438+February is the driest month, with an average precipitation of only 253 mm. However, in terms of spatial distribution, the precipitation in different areas of Hong Kong varies greatly. For example, Henglan Island is only 1, 200mm, and it is over 3,000mm near Tai Mo Shan, with a difference of more than 1 times. The worst weather affecting Hong Kong is tropical cyclones, strong winter monsoon, frequent thunderstorms and strong winds from April to June, and occasional tornadoes and hail. In particular, typhoons carrying heavy rains often cause flash floods to wash down houses and block traffic. 1993 has the most abnormal weather phenomena. The seasonal temperature changes greatly, with the cold wave lasting especially in June 5438+1October, while it is very hot and rainy in summer from July to August. Tropical cyclones were frequent during the year, and the No.8 gale or storm signal was hoisted four times, only one less than the record set by 1964. The long hurricane season lasts from the end of June to the beginning of June. In addition to the monsoon rainfall in June, tropical cyclones also brought a lot of heavy rain, especially in September, Dadi and165438+1Ella in October. 1993 The total precipitation was 2343.9 mm, 6% more than normal. 1993 65438+ 10, the longest cold wave recorded by the meteorological station. The daily minimum temperature from 15 to 30 16 is lower than 12 12, of which/kloc-0. The weather in February was unusually warm because there was no strong cold air from the north. According to the records, the monthly average temperature 18 12 and the daily average minimum temperature 16.438+02 are the fourth highest temperature recorded in February. The monthly precipitation is 1mm, which is only 2% of the normal precipitation of 48mm in February, making it the seventh driest February in Hong Kong.

Tropical hurricane

All tropical cyclones affecting Hong Kong originate in the Northwest Pacific and the South China Sea. There are about 20-30 tropical cyclones every year, of which more than 80% occur from June to 10. Hong Kong is threatened by about 5-6 tropical cyclones every year. According to their intensity, tropical cyclones invading Hong Kong can be divided into the following categories: tropical depression, tropical storm and strong tropical storm. When the tropical cyclone is about 700 kilometers southeast of Hong Kong, the weather in Hong Kong is sunny, extremely hot, the wind is weak, the wind direction is uncertain, and there are some thunderstorms at dusk. As the tropical cyclone approaches Hong Kong, the air pressure drops significantly, the wind increases, the weather deteriorates and the rain increases. When the tropical cyclone center (commonly known as the "eye") approaches Hong Kong, the wind direction will change with the shift of the eye. If the eye passes in the north or northeast of Hong Kong, the wind direction will change from northeast wind to northwest wind, and then to west wind or southwest wind; If the eye of the eye passes south of Hong Kong, the wind direction will change from northeast wind to east wind, and then to southeast wind or south wind; If the eye of the eye passes in front of Hong Kong and the wind reaches gale level, it can turn in any direction and then turn in the opposite direction. When the wind direction changes, there is a short windless state; After the wind direction changed, it strengthened again until the tropical cyclone left Hong Kong and moved northward. Generally speaking, tropical cyclones transit within a few hours, but the heavy rain they cause often lasts for several days. Compared with when the tropical cyclone approaches, it rains more when the tropical cyclone leaves. After the tropical cyclone moved away from Hong Kong, the weather turned fine and returned to normal summer weather.

Storm disaster

Typhoon is one of the major natural disasters in Hong Kong. Most typhoons in Hong Kong occur from June to September every year, especially from August to September. On average, five to six tropical cyclones threaten Hong Kong every year. About one of them approached Hong Kong, bringing strong winds. About once every ten years, a big typhoon passes through Hong Kong, and the wind force exceeds 12. Typhoons often bring heavy rain, strong winds and tides. The continuous rainstorm caused landslides and floods, and the disaster was greater than the strong wind. In some bays of Hong Kong, especially some headlands of Tolo Harbour, whenever a typhoon blows ashore, the seawater is often squeezed and expanded, resulting in flooding and affecting coastal areas. In the past century, the most serious typhoon disasters in Hong Kong are 1874, 1906, 1923, 1937, 1962,197/year. Due to the gradual development and improvement of typhoon forecasting and early warning in Hong Kong, the harm caused by typhoons to Hong Kong has gradually decreased.