Why is the autumn sky so high?

This is determined by the climate characteristics in autumn.

first, the days get shorter and the nights get longer after autumn. In the northern hemisphere, after entering autumn, the direct sunlight on the ground around the summer solstice gradually becomes oblique, and the time of day gradually becomes shorter and the time of night gradually becomes longer. During the day, the ground absorbs less heat from sunlight than in summer, and the water evaporated from the ground into the air also decreases.

second, after autumn, the temperature drops. With the gradual withdrawal of warm and humid air and the gradual entry of cold air, and gradually occupying most provinces and regions in China, the temperature begins to decrease, which will also reduce the evaporation of water vapor on the ground.

The combination of the above two points will reduce the number of clouds in the sky. Even if there are clouds, they are only a faint layer with good visibility. As a result, the clear sky in Wan Li during the day and the starry sky at night make people feel that the autumn sky is particularly high.

Extended data:

Climatic characteristics in autumn:

Generally speaking, in autumn, the sun's altitude angle decreases and the temperature decreases; The autumn wind is cool, the summer heat disappears, the fruits are full of branches, and the fields are golden.

in autumn, the summer monsoon gradually weakens, and it transits to the winter monsoon, with frequent cyclone activities, more precipitation on the front and great changes in temperature.

it is easy to have intermittent rainy weather in early autumn.

In mid-autumn, controlled by the high-pressure weather system, it is easy to have crisp autumn weather with high sky, light clouds and sunny days, that is, the so-called "spring in October" weather.

in late autumn, the influence of cold air in the north began to increase, and the weather conversion process between cold and warm, sunny and rainy was frequent, and the temperature fluctuated greatly.

Reference: Baidu Encyclopedia-Autumn