It's getting cold.

Autumn is like a beautiful poem, and the sky is crisp. Looking at those clouds, leaves and raindrops, people can't help but think of beautiful things. Some friends don't know when autumn will officially start. Here, I have compiled some information that everyone needs, hoping that everyone can learn from it.

When does the official autumn begin? When does the official autumn begin?

There is no definite time to officially enter autumn, because whether to enter autumn depends on the temperature, and the influencing factors of temperature are various. In meteorology, autumn has strict classification standards. Generally speaking, there are two ways to judge autumn. One is that the average temperature for five consecutive days is between 10℃ and 22℃, and the other is that the moving average temperature for five consecutive groups is low. At 22 degrees Celsius? (The moving average temperature is to add up the five-day average temperature and divide it by 5. )

At present, the division of the four seasons in China is often based on the change of temperature, using the modern scholar Zhang Baokun's "climate average temperature". According to the climate average temperature method, there are two main criteria for judging autumn. First, the average daily temperature for five consecutive days is between 10℃ and 22℃, which can be regarded as autumn and become "shrinking table"; Second, the average temperature of five consecutive groups is lower than 22℃. A set of moving average temperatures refers to the average temperature of the day plus the average temperature of the previous four days divided by 5 to get the five-day moving average temperature, which is the "sliding standard". Entering autumn means that the hot weather has passed and it is beginning to cool down.

Characteristics of autumn

Autumn, also known as autumn, is the third season in a year, and it is the transition season from summer to winter. From September to 1 1 month in the northern hemisphere, and from March to May in the southern hemisphere, the astronomical cycle starts from the autumnal equinox. Last winter solstice. Meteorologists study the phenological standard: after the intense heat, the average temperature for five days stays below 22 degrees, even if it enters autumn, the autumn below 10 degrees ends. The most obvious change in the natural landscape is in the trees. In cities, many fallen leaves will be cleaned up, and in mountains, many tourists will come to see the red leaves. In autumn, the most obvious change of natural landscape is in trees. Urban society began to clean up a lot of fallen leaves, and many tourists came here to see the maple red in the mountains and plains.

Autumn is a transitional season from summer to winter. The lunar calendar starts from autumn to winter, from July to September, the solar calendar from September to 1 1 month, and the astronomical cycle from autumnal equinox to winter solstice. The main meteorological disasters in autumn are: autumn rain in the west, cold dew wind in the south, frost and chilling injury at low temperature. Generally speaking, in autumn, the solar altitude angle gradually decreases and the temperature gradually drops.

What to eat in autumn

Suitable for eating bananas, pears, carambola, hawthorn, fresh dates, black-bone chicken soup and other foods in autumn, and also suitable for drinking Chinese medicines such as Ophiopogon japonicus and chrysanthemum.