Autumn is divided into early autumn, Mid-Autumn Festival and late autumn. What time?

Every quarter is three months. The first month in beginning of autumn is early autumn, the middle month is Mid-Autumn Festival, and the last month is late autumn. After late autumn, it will enter winter.

Knowledge expansion

In autumn, the most obvious change of natural landscape is in trees. The city will begin to clean up a lot of fallen leaves, and many tourists will flock to the mountains to watch the red leaves. Autumn, the third season of the year, is a transitional season from summer to winter. The lunar calendar is from beginning of autumn in July to beginning of winter in September, the solar calendar is from 9: 00 to 1 1, and the astronomical vernal equinox starts from the winter solstice.

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.

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.

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, some areas in the Jianghuai area interpret the heat as "being in the heat". 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.

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.

Cold Dew

Every year1October 8 or 9, when the sun reaches longitude 195, it is cold dew. "Twenty-four solar terms" said: "September solar terms, dew will condense when it is cold." 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.

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.