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How are the four seasons divided? Division criteria and methods of four seasons

There are four seasons in a year: spring, summer, autumn and winter, but the four seasons in some places are not clear, and they may not even feel the changes of the seasons at all. So what are the criteria and methods for dividing the four seasons? This article brings you the division standards and methods of the four seasons. Let's have a look.

division criteria and methods of four seasons

1. Astronomical division from the perspective of astronomical phenomena, the change of the four seasons is the seasonal change of the length of day and night and the height of the sun. In a year, the season with the longest day and the highest sun height is summer, the season with the shortest day and the lowest sun height is winter, and the transition season between winter and summer is spring and autumn. To this end, the astronomical division of the four seasons begins with the spring equinox (March 21), the summer solstice (June 21), the autumn equinox (September 21) and the winter solstice (December 21). That is: the spring equinox to the summer solstice is spring, the summer solstice to the autumn equinox is summer, the autumn equinox to the winter solstice is autumn, and the winter solstice to the spring equinox is winter.

2. The meteorological division method in the meteorological department usually takes March to May of the Gregorian calendar as spring, June to August as summer, September to November as autumn, December to February of the next year as winter, and often takes January, April, July and October as the representative months of winter, spring, summer and Autumn.

3. The ancient division method starts with the beginning of spring (February 4 or 5), the beginning of summer (May 5 or 6), the beginning of autumn (August 7 or 8) and the beginning of winter (November 8 or 9).

4. Chinese people traditionally use the lunar month to divide the four seasons. Spring is from January to march of the lunar calendar, summer is from April to June, autumn is from July to September, and winter is from October to December. The first day of the first month is the first day of the whole year and the first day of spring, so it is also called the Spring Festival.

This division is based on the weather (five days as a weather). The average temperature is used as the temperature index for dividing the four seasons. Summer begins when the average temperature is above 22 ℃, winter begins when the average temperature is below 10 ℃, and spring and autumn begins when the average temperature is between 10 ~ 22 ℃. From 10 ℃ to 22 ℃ is spring, and from 22 ℃ to 10 ℃ is autumn.