When the earth revolves around the sun for half a week, the direct point of the sun moves from the tropic of cancer to the tropic of Capricorn, and the solar heat gained by the northern hemisphere gradually decreases, from summer to autumn, and then to winter;
On the other hand, the southern hemisphere goes from winter to spring, and then to summer. But the earth's orbit around the sun is not a standard perfect circle, so the summer in the southern hemisphere is slightly hotter than that in the northern hemisphere, and the winter is colder than that in the northern hemisphere.
Extended data
At different latitudes, seasonal changes have different characteristics.
1, temperate zone
Subtropical seasons are distinct.
2. Cold zone
It is very cold all year round in the frigid zone, but the temperature difference in Xia Dong is still obvious. In summer and winter, there will be extreme days and nights.
3. Tropical
With the change of seasons, there will be direct sunlight, and there is little difference in temperature between seasons. Meteorology is mainly affected by dry and wet conditions and monsoon.
Baidu Encyclopedia-Spring, Summer, Autumn and Winter