What are the phenological phenomena in beginning of spring?

Spring: Dongfeng, willow, grass, spring rain, swallows, pears, peach blossoms, spring outing, kites, melting ice and wheat seedlings.

Summer: scorching sun, cicadas, dragonflies, rainstorms, lotus flowers and stars.

Autumn: Harvest fields, numerous fruits, fallen leaves, red maple leaves, residual lotus, wild geese flying south and autumn chrysanthemums.

Winter: snow, north wind, rime, window flowers, dead trees, warm sun and plum blossoms.

Spring, summer, autumn and winter, also known as the "four seasons", are the results of the earth's orbit around the sun. Spring begins with "beginning of spring" in the 24 solar terms, and summer begins with "Long Summer". Autumn begins with beginning of autumn; Winter begins in beginning of winter.

Reasons for the formation of spring, summer, autumn and winter

Spring, summer, autumn and winter are formed because the earth revolves around the sun. The earth has been spinning from west to east, and at the same time it goes around the sun. Because of the revolution of the earth, the direct point of the sun changes on the surface of the earth.

The brightest areas on the earth are places where the sun shines directly, such as the Tropic of Cancer, Tropic of Capricorn and Equator. Oblique areas are dark, especially where the oblique angle is large, and the light is weak, such as the north and south poles. Affected by the revolution of the earth and the inclination of the earth's axis, the areas where the earth is exposed to direct sunlight will be different, and the temperature will change accordingly, thus forming four seasons.

When the sun shines directly on the equator, it is hottest near the equator. The farther away from the equator, the greater the sun's oblique angle and the lower the temperature. At this time, the northern hemisphere is a little far from the equator. Is spring here yet? 4.？ When the sun shines directly on the equator, it will gradually move north. On June 2 1 and June 22, the sun will shine directly on the Tropic of Cancer. At this time, it is the hottest near the Tropic of Cancer, and the northern hemisphere is strongly irradiated by the sun. It's summer.