When does autumn begin and end?

1. In terms of months, the lunar calendar is from beginning of autumn to beginning of winter from July to September, the solar calendar is from 9: 00 to 1 1, and astronomy is from the autumnal equinox to the winter solstice. In China, autumn begins in early autumn, passes through early autumn, Mid-Autumn Festival and late autumn, and finally ends in early winter.

2. Meteorologically, autumn in north temperate zone is from August 23rd (summer) to165438+1October 20th (light snow); Autumn in the south temperate zone is from February 19 (rain in the northern hemisphere) to May 2 1 (xiaoman in the northern hemisphere).

3. In terms of temperature, the periods of 10~22℃ are spring and autumn respectively.

Autumn?

Also known as autumn, the third season of the year, the transitional season from summer to winter, from September to 165438+ 10 in the northern hemisphere, from March to May in the southern hemisphere, from the autumnal equinox to the winter solstice in astronomy [1]? . The standard for meteorologists to study phenology is: after the intense summer heat, the average temperature for five days is stable below 22 degrees, which means that it is autumn, and it is over when it is below 10 degrees.

The most obvious change in the natural landscape is in the trees. Many fallen leaves will be cleaned up in the city, and many tourists will flock to the mountains to see the red leaves.

Definition of words

1, Korea's "On Salt and Iron": "The words are better than Tang Yu, and the meaning is higher than autumn. There are gorgeous words, but I didn't actually see them. " Yu Xin's Xiao Yuan Fu in the Northern Zhou Dynasty: "It's not terrible in summer, but sad in autumn." The poem "Bodhisattva Man" written by Yin E of the former Shu Dynasty reads: "The clouds are long and the autumn is white, and I sit by the window alone to peep at the smoke."

2. Tang Zhangwei's poem "Nine Days": "Lin Qiu doesn't know spring, so it's easy to travel." Hu Shi's Trial Collection on the 24th Night of November: "Now they say that I am getting better soon, and the beautiful autumn has long passed."

As can be seen from the date distribution map of beginning of autumn in China, Northeast China is the earliest place in beginning of autumn in eastern China. In autumn, the cold air in the north is constantly invading, but its power is not very strong. Autumn weather often forms in northern China, and continuous autumn rain often appears in West China.

The main meteorological disasters in autumn are: autumn rain in West China, cold dew wind in the south, frost and chilling injury at low temperature. Generally speaking, in autumn, the solar altitude angle decreases and the temperature decreases; The autumn wind is cool, the summer heat is gone, the fruits are covered with branches, and the fields are golden.

Autumn alias

High autumn (meaning crisp autumn)

Su Qiu? Bai Qiu (Mid-Autumn Festival in Five Elements Thought = Gold = White)

Bai Di (the god in charge of autumn)

Autumn (autumn = gold; Harvest? Color of plants)

Sanqiu (early autumn, mid-autumn and late autumn)

Nine autumns (autumn 90 days = three months)

Autumn solar terms

There are six solar terms in autumn, namely beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew and First Frost.

An atmosphere/scene

The temperature will gradually drop in autumn, but it is generally slower than in winter. Due to the difference of dry and wet conditions, there will be cold and rainy weather conditions or dry and cool weather conditions in different regions. In the cold late autumn, due to the large temperature difference between day and night, the water vapor transpiration during the day will condense at night, either dew or frost.

astronomy

In autumn, the direct point of the sun gradually moves south from the northern hemisphere, passes through the equator after the autumnal equinox, and the sun directly shines in the southern hemisphere. Seen from the northern hemisphere, the angle of the sun gradually becomes lower, and the gap between day and night becomes smaller. At the autumnal equinox, the length of day and night is equal. In autumn, the distance between the earth and the sun is from far to near. Seen from the ecliptic plane, the sun is on the background of Leo, Virgo and Libra.

Beginning of Autumn

Beginning of autumn is the 13 of the 24 solar terms. On August 7th or 8th every year, beginning of autumn is considered as the time when the sun reaches 135. "Autumn" means that summer is cool, which means the beginning of autumn. But in early autumn, the weather in Jianghuai area is still very hot.

According to the standard of dividing seasons according to the average temperature, it must be that the average temperature for five days is below 22℃ to be considered as autumn. According to this standard, the Jianghuai area generally enters autumn in the middle and late September. After beginning of autumn, although the summer heat is hard to disappear for a while, there is still the afterglow of "autumn tiger", but the general trend is that the weather is getting colder and colder. The daily temperature range is gradually obvious, which is often very hot during the day and very cold at night.

Autumn actually means that the crops are about to mature. After beginning of autumn, late rice in most parts of South China started jointing and heading, and cotton bolls cracked. Mid-season rice and summer corn entered the stage of grain filling maturity. In the east and west of South China, the task of drought and flood control is still very arduous. South China after beginning of autumn is still in midsummer, but "beginning of autumn is full of yellow in ten days", and a golden "autumn" is coming soon?

The heat is over

Summer is 14 of the 24 solar terms. "Out" means going. In summer, the heat stops here, that is, in summer, the hot summer will pass, the temperature will gradually drop, and the rainfall will gradually decrease. However, this is only a general rule. In the Jianghuai area, the difference is bigger year by year. In some years, the weather during the hot summer is even hotter than that in summer, resulting in the so-called "autumn tiger" weather. Because of this, the intense heat in the Jianghuai area is interpreted as "the intense heat in midsummer". Therefore, remind people to pay attention to heatstroke prevention at this time. The temperature difference between day and night in the north is gradually increasing, so it is necessary to add clothes in time in the morning and evening to prevent colds.

The conditions of warm day and cool night are very beneficial to the production and accumulation of dry matter of crops, and the crops mature quickly. There is a folk proverb called "overnight in summer, the fields have changed." So remind farmers and friends to arrange field farming in time according to weather changes.

Autumn Equinox

The autumnal equinox is a solar term representing seasonal changes. On the day of the autumnal equinox, the sun is located at longitude 180 degrees, and the sunlight is almost direct to the equator, and day and night are almost equal. At this time, the waiting temperature in the southern region has generally dropped below 22℃, and it has entered a cool autumn. "An autumn rain and a cold". The cold air from the south meets the warm and humid air that gradually decays, resulting in repeated rainfall and the temperature dropping again and again. In the northern part of the northwest plateau, the daily minimum temperature has dropped below 0℃, and you can already see the magnificent snow scene flying all over the sky and the earth wrapped in silver.

After the autumnal equinox, rainfall in most parts of the south decreased significantly, and heavy rain and heavy rain rarely appeared. However, rainy days increase, rainy days are frequent, and the night rain rate is high. Li Shangyin, a famous poet in the Tang Dynasty, famously said, "It rains late in autumn pond", which vividly describes the climate characteristics of autumn rainy nights in the south.

It is rainy and humid in autumn in the south and Liangshan Prefecture, which has great influence on autumn harvest, autumn ploughing and autumn planting. It is necessary to grasp the sun, control soil moisture and prevent waterlogging, and do a good job in the quality and progress of Sanqiu production. At the same time, we should make full use of the meteorological conditions of rainy autumn and good soil moisture, seize the opportunity to do a good job in afforestation, and strive to improve the survival rate of saplings.

Cold Dew

Every year1October 8 or 9, when the sun reaches longitude 195, it is cold dew. "Twenty-four solar terms" said: "In September, the dew is cold and will condense." Cold dew means that the temperature is lower than that of the white dew, and the dew on the ground is colder and will soon condense into frost. In the cold dew season, Nanling and the vast area to the north have entered autumn, and the northeast and northwest regions have entered or are about to enter winter. In the capital Beijing, you can see the first frost in many years. In addition to the perennial snow on the Qinghai-Tibet Plateau, it has generally begun to snow in the northeast and northern Xinjiang.

After the cold dew, the cold air in the north has a certain influence, and most parts of China are controlled by cold high pressure, and the rainy season is over. The weather is often warm during the day and cool at night, with clear skies and Wan Li, which is very beneficial to the autumn harvest. Thunderstorms have disappeared in most parts of Chinese mainland, and only Yunnan, Sichuan and Guizhou can hear thunder. The precipitation in June 5438+ 10 in North China is generally only half or less than that in September, while in Northwest China it is only a few millimeters to more than 20 millimeters. Drought and lack of rain often bring difficulties to timely sowing of winter wheat and become one of the main limiting factors for high yield of dry land wheat.

At this time, it is still autumn rain in Hainan and Southwest China, and rainy weather will also occur in Jianghuai and Jiangnan in a few years, which will have a certain impact on autumn harvest and autumn planting.

"Cold dew doesn't pick cotton, and first frost doesn't complain." . When the weather is good, we should pay close attention to harvesting cotton. When the temperature drops early, we can take it back when the temperature is not too low. One-season late rice is about to mature in Jianghuai and Jiangnan, and double-season late rice is filling. Pay attention to intermittent irrigation to keep the fields moist. The southern rice areas should also pay attention to prevent the harm of "cold dew wind". North China should hurry to sow wheat. At this time, in case of drought and little rain, we should try our best to accumulate soil moisture, grab soil moisture for sowing, and ensure that sowing is completed before and after the first frost. We must not passively wait for rain to lead to planting early crops and late wheat. Before and after the cold dew is the suitable sowing date for direct seeding rape in the Yangtze River basin, and the variety arrangement should be that Gan Lan-type varieties should be sown first, and then cabbage-type varieties should be sown. Those who sow green manure in the south of Huaihe River should be cleaned up, and those who have emerged should be cleaned and drained to prevent waterlogging. The tuber swelling of sweet potato in North China Plain gradually stopped, and the probability that the morning temperature was lower than 10℃ or lower gradually increased. According to the weather conditions, we should pay close attention to harvesting and strive to finish it before the first frost, otherwise potato tubers will "harden their hearts" because they are frozen underground for too long, reducing the value of eating, feeding and industrial utilization, and cannot be stored or used as seeds.

Frost's Descent

The solar term of the first frost is1October 23rd or 24th every year, 10. According to the "Twenty-four solar terms": "In mid-September, the gas is cold and condensed, and the dew is like frost." It can be seen that the first frost refers to the beginning of frost. However, China has a vast territory, and the climate varies greatly from place to place. "The first frost in the first frost" reflects the climate characteristics of the Yellow River Basin. As far as the annual frost days are concerned, there are frost and snow in some parts of the Qinghai-Tibet Plateau even in summer, and the annual frost days are over 200, which is the place with the largest number of frost days in China. The annual frost days in eastern Tibet, southern Qinghai, Qilian Mountains, western Sichuan Plateau, northwestern Yunnan, Tianshan Mountains, Altai Mountains, western mountainous areas of northern Xinjiang, northeast China and eastern Inner Mongolia all exceed 100 days, and the vast areas south of Huaihe River, Hanshui River and east of Dongpo of Qinghai-Tibet Plateau are all below 50 days, with only the annual frost days in the south of 25 north latitude, Sichuan Basin, south of Fuzhou and coastal areas of Guangdong and Guangxi being/kl.

The appearance of frost shows that the lowest ground temperature has reached below 0℃, which will have a certain impact on crops. The first frost in autumn is called the first frost. The earlier the first frost, the greater the harm to crops. The first frost in all parts of China is gradually delayed from north to south and from mountainous areas to plains. Except for areas with frost all the year round, frost first appeared in the north of Daxing 'anling, usually at the end of August. The first frost in most parts of Northeast China, Inner Mongolia and Northern Xinjiang is mostly in September. 10 Frost has appeared in Shenyang, Chengde, Yulin, Qamdo and Lhasa. 165438+1Frost has been seen in Shandong Peninsula, Zhengzhou, Xi 'an and northwest Yunnan in early October; Frost did not appear in eastern China, Hanshui and Yunnan provinces until the beginning of 65438+February. First frost from Xiamen and Guangzhou to Baise and Simao is 65438+1early October after the New Year.

In the first frost season, the cool autumn wind blew to Guangzhou, the flower city. The average temperature in the northeast, eastern Inner Mongolia and most of the northwest has been below 0℃, the soil has frozen, and the winter crops have stopped growing and entered the wintering period. For soybean harvest in North China, spring varieties should be selected for late wheat that has not been sown, and seedlings should be checked and replanted for those that have emerged. The Yangtze river basin is in the golden season of winter wheat sowing. Rape has generally entered the two-leaf stage, so it is necessary to sow in time, weed in intertillage and control aphids. Late-maturing rape that has not been planted due to floods in disaster areas can be sown with wet ash manure first, and then sown indoors to accelerate the emergence of seedlings. "If the first frost doesn't harvest the crops, it will lose a reed one day." When the late rice is ripe, we should pay close attention to harvesting to prevent birds from damaging the seeds. The Chinese cabbage in North China is about to be harvested, so the later management should be strengthened.

In the first frost season, most parts of China enter the dry season, so we should attach great importance to forest protection and fire prevention.