Why is it hotter in the south than in the north?

Winter is from December to February of the following year, and January, April, July, and October are often regarded as the representative months of winter, spring, summer, and autumn. 3． The ancient division method uses the beginning of spring (February 4 or 5) as the beginning of spring, the beginning of summer (May 5 or 6) as the beginning of summer, the beginning of autumn (August 7 or 8) as the beginning of autumn, and the beginning of winter (November 8th or 9th) as winter begins.

4. Lunar calendar division method: Chinese folk custom uses lunar calendar months to divide the four seasons. The months from January to March of the lunar calendar each year are spring, the months from April to June are summer, the months from July to September are autumn, and the months from October to December are winter. The first day of the first lunar month is the first day of the whole year and the first day of spring, so it is also called the Spring Festival.

The spring equinox (3.21), the summer solstice (6.22), the autumnal equinox (9.23), the east solstice - (12.22) these solar terms.

Solar terms: Solar terms can be understood in two ways: one, one of the twenty-four solar terms. Starting from Xiaohan, every 30° increase in the yellow longitude of the sun is another solar term. It includes Xiaohan, Beginning of Spring, Jingzhe, Qingming, Beginning of Summer, Mangzhong, Xiaoshu, Beginning of Autumn, Bailu, Handew, Beginning of Winter and Heavy Snow. Called the twelve solar terms. 2. A general term for the twenty-four qi. Solar terms are generally calculated based on the solar calendar. The earth orbits the sun once every 365 days, 5 hours, 48 ??minutes and 46 seconds (accurately), and it also rotates once every 24 hours. Since the orbital plane of the Earth's rotation is not consistent with the equatorial plane, but maintains a certain inclination, the position of the direct sunlight hitting the Earth is different throughout the year. In the northern hemisphere, when the sun shines directly at 23.5 degrees north latitude, it is called the summer solstice in astronomy; when the sun shines directly at 23.5 degrees south latitude, it is called the winter solstice; the summer solstice and winter solstice mean that it has reached the middle of summer and winter. When the sun shines directly on the equator twice in a year, it is the vernal equinox and the autumnal equinox, which is the middle of spring and autumn. The days and nights are as long as each other in these two days. The eight solar terms that reflect the changes in the four seasons are: the beginning of spring, the vernal equinox, the beginning of summer, the summer solstice, the beginning of autumn, the autumnal equinox, the beginning of winter, and the winter solstice. Among them, the beginning of spring, the beginning of summer, the beginning of autumn, and the beginning of winter are collectively called "Four Lis", which means the beginning of the four seasons. There are five solar terms that reflect temperature changes: minor heat, major heat, extreme heat, minor cold, and major cold. There are seven solar terms that reflect weather phenomena: rain, grain rain, white dew, cold dew, frost, light snow, and heavy snow. There are four solar terms that reflect phenological phenomena: Jingzhe, Qingming, Xiaoman, and Eawn.

The solar terms all refer to the time, that is, when the sun's ecliptic longitude is equal to 15 degrees, it is the Qingming Festival. And spring, summer, autumn and winter are seasons.

1. The geographical boundary of my country's population distribution

It is roughly bounded by a straight line drawn between Heihe City in Heilongjiang Province and Tengchong City in Yunnan Province. The southeast of this line has a large population, and the northwest of this line has a large population. The population is small.

2． Terrain ladder boundary

(1) The boundary between the first ladder and the second ladder: starting from the Kunlun Mountains in the west, passing through the Qilian Mountains and going southeast to the eastern edge of the Hengduan Mountains.

(2) The boundary between the second step and the third step: from northeast to southwest are the Daxingan Mountains, Taihang Mountains, Wushan Mountains, and Xuefeng Mountains.

3. Topographic area boundaries

(1) The boundary between the Inner Mongolia Plateau and the Northeast Plain: Daxinganling.

(2) The boundary between the Loess Plateau and the North China Plain: Taihang Mountains.

(3) The boundary between the Sichuan Basin and the middle and lower reaches of the Yangtze River Plain: Wushan.

(4) The boundary between Yunnan-Guizhou Plateau and Qinghai-Tibet Plateau: Hengduan Mountains.

(5) The boundary between the Junggar Basin and the Tarim Basin: the Tianshan Mountains.

(6) The boundary between the Qinghai-Tibet Plateau and the Tarim Basin: the Kunlun Mountains.

(7) The boundary between the Loess Plateau and the Hanshui Valley: Qinling Mountains.

(8) The boundary between the Hexi Corridor and the Qaidam Basin: Qilian Mountains.

(9) The boundary between the Sichuan Basin and the Hanshui Valley: Daba Mountains.

(10) The boundary between the Inner Mongolia Plateau and the Loess Plateau: the ancient Great Wall.

(l1) The boundary between the middle and lower reaches of the Yangtze River Plain and the North China Plain: Huaihe River.

4. Climatic boundaries

(1) The monthly 0°C isotherm (also the boundary between subtropical, warm temperate and plateau climate zones): roughly along the southeastern edge of the Qinghai-Tibet Plateau, passing eastward through the Qinling Mountains and the Huaihe River.

(2) The 800 mm constant precipitation line (the boundary between humid and semi-humid areas): along the southeastern edge of the Qinghai-Tibet Plateau, passing eastward through the Qinling Mountains and the Huaihe River.

(3) 400 mm constant precipitation line (the boundary between semi-humid and semi-arid areas): from the western slope of the Greater Khingan Mountains through the vicinity of Zhangjiakou, Lanzhou, and Lhasa to the eastern Himalayas.

(4) The 200 mm constant precipitation line (the boundary between semi-arid and arid areas): roughly passes through the Yinshan Mountains, Helan Mountains, Qilian Mountains, Bayan Hara Mountains and the Gangdise Mountains.

5. River boundary

(1) The boundary between the outflow area and the inflow area: the northern section is roughly along the Daxinganling-Yinshan Mountain-Helan Mountain-Qilian Mountain (eastern end) line, and the southern section is closer to the 200 mm precipitation line.

(2) The watershed between the Yangtze River system and the Yellow River system: the Bayan Har Mountains and the Qinling Mountains.

(3) The watershed between the Yangtze River water system and the Pearl River water system: Nanling.

(4) The watershed between the Lancang River and the Nu River: Nu Mountain.

(5) The watershed between the Yangtze River Basin and the southeast coastal river basins: Wuyi Mountain.

6. Boundaries of three natural areas

(1) The boundary between the eastern monsoon area and the northwest arid and semi-arid area: the 400 mm constant precipitation line.

(2) The boundary between the Qinghai-Tibet alpine zone and the eastern monsoon zone: the 3000-meter contour.

(3) The boundary between the northern part of the Qinghai-Tibet alpine zone and the arid and semi-arid zone in the northwest: roughly from the Kunlun Mountains to the east through the Altun Mountains and the Qilian Mountains.

7. Natural area boundaries

(1) Natural area boundaries within the eastern monsoon zone

① The boundary between the southern region and the northern region (the warm temperate humid region of North China and the subtropical humid region of Central China): Qinling-Huaihe River (0°C isotherm in January, daily average temperature >10°C accumulated temperature 4500°C isotherm).

② The boundary between the humid and semi-humid areas in the Northeast temperate zone and the humid and semi-humid areas in the warm temperate zone in North China: the daily average temperature is >10°C and the active accumulated temperature is 3200°C.

③The boundary between the humid subtropical areas in Central China and the humid tropical areas in South China: daily average temperature >10℃ accumulated temperature 7500℃ isoline

(2) Natural area boundaries within the arid and semi-arid areas of northwest China .

The boundary between the temperate grassland area of ??Inner Mongolia and the northwest temperate and warm temperate desert areas: the Helan Mountain line, which is equivalent to the 200 mm precipitation line.

8. Boundary of agricultural activities

(1) The boundary between pastoral and agricultural areas: generally close to the 400 mm precipitation line.

(2) The boundary between paddy field area and early cropping area: Qinling Mountains and Huaihe River.

9. Administrative district boundaries

(1) The boundary between southern and northern Xinjiang (the boundary between mobile dunes and fixed and semi-fixed dunes): Tianshan Mountains.

(2) The boundary between Hubei Province and Chongqing City: Wushan.

(3) The boundary between Fujian Province and Jiangxi Province: Wuyi Mountain.

(4) The boundary between Guangdong Province and Hunan Province: Nanling.

(5) The boundary between the Tibet Autonomous Region and the Xinjiang Uygur Autonomous Region: Kunlun Mountains.

(6) The boundary between Gansu Province and Qinghai Province: Qilian Mountains.

(7) The boundary between Sichuan Province and Shaanxi Province: Daba Mountains.

10. Comprehensive geographical boundaries

(1) The Qinling Mountains-Huaihe River line is an important geographical dividing line in my country. The landscapes of the north and south of this line are very different:

①The southern part of the Loess Plateau Boundary

②Roughly where the 0°C isotherm and 800mm precipitation isotherm pass in January

③The boundary between the subtropical zone and the warm temperate zone

④Moist The boundary between the subtropical zone and the semi-humid zone

⑤The boundary between subtropical evergreen broad-leaved forest and temperate deciduous broad-leaved forest

⑥The boundary between rivers with and without ice periods

⑦The boundary between agricultural paddy fields and dry land, the three-crop system in two years and the two-crop system in a year, and rice and wheat cereals

⑧The boundary between the Yangtze River system and the Yellow River system

(2 ) The Daxingan Mountains are also an important geographical dividing line in my country, and the landscapes on its east and west sides are also quite different:

①The place where the 400 mm constant precipitation line passes

②Monsoon area and non-monsoon area Division boundary

③The boundary between the inflow area and the outflow area

④The boundary between the pasture area and the agricultural area

⑤The boundary between the Inner Mongolia Plateau and the Northeast Plain Boundary line

⑥The place where the boundary between the second step and the third step of my country's terrain passes

⑦The place where the boundary between forest landscape and grassland landscape passes.

On the summer solstice on June 22, the sun shines on the Tropic of Capricorn, marking the longest day of the year in the northern hemisphere. The sun also shines directly on the Tropic of Capricorn. Geographically speaking, the south is hotter than the north. In fact, the hottest month is July.