The twenty-four solar terms are unique to the Chinese calendar and first appeared in the Warring States Period. It represents twenty-four different positions of the Earth in its orbit, depicting the pattern of climate changes throughout the year. The apparent motion of the earth as it rotates around the sun is 360 degrees, which is divided into 24 equal parts (it was initially divided into 12 equal parts), and each part of 15 degrees (about half a month) has a solar term. There are 24 solar terms throughout the year, which are called: Beginning of Spring, Rain, Waking of Insects, Vernal Equinox, Qingming, Guyu, Beginning of Summer, Xiaoman, Mangzhong, Summer Solstice, Minor Heat, Great Heat, Beginning of Autumn, End of Summer, White Dew, Autumn Equinox, Cold Dew, Frost Descent, Beginning of winter, light snow, heavy snow, winter solstice, light cold and severe cold.

1. Beginning of Spring: February 4th or 5th every year, which is the beginning of spring.

2. Rain: Every year on February 19th or 20th, when winter turns to spring, the temperature begins to rise and the air humidity continues to increase, but cold air activities are still very frequent.

3. Waking of Insects: On March 5 or 6 every year, it means that hibernating organisms that have been hibernating in the soil in winter begin to move. Before and after the Waking of Insects, it is cold and warm at first, and the temperature and wind change greatly.

4. Vernal Equinox: On March 20 or 21 every year, the sun shines directly on the equator, and the day and night are almost equal in length. Overwintering crops in vast areas of my country will enter the spring growth stage.

5. Qingming Festival: On April 4 or 5 every year, the temperature rises and the weather gradually becomes warmer.

6. Grain Rain: On April 20 or 21 every year, there is more rain, which is beneficial to the growth of cereals.

7. Beginning of Summer: On May 5 or 6 every year, all things grow and flourish.

8. Xiaoman: On May 21st or 22nd every year, the grains of summer crops such as wheat begin to be full but not mature.

9. Eawn: On June 5 or 6 every year, the sun moves to 75 degrees of ecliptic longitude. Wheat and other awning crops are mature and seeds can be collected.

10. Summer Solstice: On June 21 or 22 every year, the sun shines directly on the Tropic of Cancer, and "the sun reaches the north, the sun reaches the longest, and the sun's shadow is short," hence the name "Summer Solstice."

11. Slight Heat: July 7 or 8 every year, the onset of summer heat, marking the entry of the hot season in most areas of our country.

12. Great Heat: July 22 or 23 every year, around the time of the midsummer period. This period is the hottest period of the year in most areas of our country, but there are also abnormal years where "the heat is not hot" and there is too much rain.

13. Beginning of Autumn: On August 7th or 8th every year, the vegetation begins to bear fruit, and it is the harvest season.

14. End of Heat: On August 23 or 24 every year, "End" means the end. When the summer heat is about to end, the weather will become cooler. Since it is the time of autumn harvest, precipitation is very precious. Chu means termination and hiding. Sushu means the end of the hot summer days.

15. White Dew: Every year on September 7th or 8th, due to the obvious shift of the direct sun point to the south, the temperature in various places drops rapidly, the weather is cool, and the water vapor close to the ground forms white on the grass and trees at night. Dewdrops, hence the name "white dew".

16. Autumn Equinox: On September 23 or 24 every year, the direct sunlight returns to the equator, making day and night equal in length.

17. Cold Dew: October 8 or 9 every year. At this time, the direct point of the sun begins to move southward, the temperature in the northern hemisphere continues to drop, the weather becomes colder, and the dew is very cold, so it is called "cold dew wind".

18. Frost Descent: Every year on October 23 or 24, the first frost period in the Yellow River Basin is usually in late October, which coincides with the "Frost Descent" season. Frost is very harmful to growing crops.

19. Beginning of Winter: Winter begins on November 7 or 8 every year.

20. Light snow: Every year on November 22 or 23, the cold air in the north strengthens, the temperature drops rapidly, and snowflakes appear in the precipitation. However, this is the first snow stage, and the amount of snow is small and not frequent. Snowfall mostly occurs after the "light snow" solar term in the Yellow River Basin.

21. Heavy snow: December 7 or 8 every year. At this time, the direct point of the sun is close to the Tropic of Capricorn, and the days are short and the nights are long in the northern hemisphere.

22. Winter Solstice: December 22 or 23 every year. At this time, the sun almost shines directly on the Tropic of Capricorn, and the northern hemisphere forms the southern solstice, the short solstice, and the long shadow solstice, which becomes the solstice of the year. The shortest day. After the winter solstice, the days in the northern hemisphere become longer and the temperature continues to drop, reaching the lowest temperature of the year.

23. Xiaohan: January 5th or 6th every year, when the climate starts to get cold.

24. Big Cold: January 20 or 21 every year is the coldest time of the year.

With the spread of the Chinese calendar, the twenty-four solar terms have spread to many parts of the world.