It is usually assumed that the rotation of the Earth around its axis causes day and night and the turning of the Earth around the Sun — the change of seasons. However, the change of seasons is associated not only with the movement of the Earth in its orbit. We consider this phenomenon in more detail.
Earth's axis is inclined to the plane of the orbit and the motion of the Earth around the Sun is always parallel to itself, and because of this, at different times, then North, the southern hemisphere receives more heat and light from the Sun.
On June 22, the day of the summer (for Northern hemisphere) solstice the earth's axis is tilted the North pole towards the Sun, and the Northern hemisphere receives more heat than the southern. Throughout the hemisphere the day is longer than night, this is the longest day of the year, and the North circumpolar region — from the latitude of 66.5° to the pole — lit all day and night, the Sun never sets, there is polar day. In the southern hemisphere is the opposite: everywhere the night longer than the day is the shortest day of the year, and in the circumpolar region, from 66,5° to the pole the Sun does not rise — the polar night. On this day the Sun at noon is in the Zenith above the parallel of 23.5° North latitude.