How many seasons are there in a year? How are they divided?

According to the meteorological classification method, in the meteorological department, March to May is usually spring, June to August is summer, September to 165438+ 10 is autumn, and 12 is winter. Refers to the four seasons of the earth in a year, which is the result of the earth's orbit around the sun.

Our earth revolves around the sun and rotates around its own axis, but the axis is not perpendicular to the orbital plane, but has an inclination of 23 degrees and 27 minutes. It is precisely because of this tilt that the direct point of the sun on the earth's surface moves between the Tropic of Cancer and the Tropic of Capricorn, thus forming four seasons: spring, summer, autumn and winter.

Extended data:

Introduction to Season 1 and Season 4:

Astronomically speaking, the division of the four seasons is determined by the orbital position of the earth around the sun. When the earth is in different positions in the orbit of revolution at different times of the year, different places on the earth receive different sunlight and different heat from the sun, which leads to seasonal changes and differences between cold and hot.

The four seasons on the earth are not only periodic changes in temperature, but also periodic changes in the length of day and night and the height of the sun. It affects or determines the movement rhythm of many things in the earth's environment, especially the adaptation of creatures.

Second, twenty-four solar terms:

Spring:

February 3 -5?

[beginning of spring (solar terms), longitude 3 15 degrees];

February 18-20.

[Rain (neutral gas), longitude 330 degrees];

March 5 -7?

[In a daze (solar terms), 345 degrees longitude];

20-22 March

Intersection point [vernal equinox (neutral qi), longitude 0 degrees];

April 4-6

Intersection [Tomb-Sweeping Day (solar terms), longitude 15 degrees];

April 19-2 1

Day Festival [Grain Rain (Zhongqi), longitude 30 degrees];

Summer:

5-7 May

Angle boundary [long summer (solar terms), longitude 45 degrees];

20-22 May

Intersection point [Xiaoman (Zhongqi), longitude 60 degrees];

5-7 June

Intersection [awn species (solar terms), longitude 75 degrees];

June 2 1-22

Intersection point [summer solstice (middle qi), 90 degrees of the yellow meridian];

6-8 July

Intersection [light summer (solar terms), longitude 105 degrees];

July 22nd-24th

Intersection [heat (Zhongqi), longitude 120 degrees];

Autumn:

August 7-9

Intersection [beginning of autumn (solar terms), longitude 135 degrees];

22-24 August

Intersection [hot in summer (neutral), longitude 150 degrees];

7-9 September

Intersection point [Millennium (solar terms), longitude 165 degrees];

22-24 September

Intersection [autumnal equinox (neutral), longitude 180 degrees];

65438+18 -9 October

Intersection [cold dew (solar terms), longitude 195 degrees];

65438+123-24 October

Day and night solar terms [first frost (neutral gas), longitude 2 10 degrees];

Winter:

165438+17-8 October

Intersection [beginning of winter (solar terms), longitude 225 degrees];

165438+122-23 October

Intersection [light snow (neutral gas), longitude 240 degrees];

65438+6 -8 February

Intersection [heavy snow (solar terms), longitude 255 degrees];

65438+February 2 1-23

Intersection [Winter Solstice Day (Zhongqi), longitude 270 degrees];

65438+15 -7 October

Sister jiao?

[Slight cold (solar terms), longitude 285 degrees];

65438+1October 20 -2 1

Jiaojie [Great cold (middle qi), 300 degrees of yellow meridian].

References:

Baidu encyclopedia-four seasons

Baidu Encyclopedia-Spring, Summer, Autumn and Winter