Winter, like other seasons, is due to the inclination of the Earth's axis, which is 23.5 ° relative to the orbital plane in which the Earth moves. Due to this tilt, different parts of the planet are exposed to different illumination by the Sun as it moves in orbit throughout the year. As a result, during this period, the rays fall at a very small angle to the earth's surface, causing them to scatter (the beam of rays) over a larger surface, water or land, rather than focusing on a smaller area, as is the case. in summer, when the beam of rays comes almost vertically. In winter, the sun is also low above the horizon, for a shorter time during the day compared to summer. The earth is illuminated, but significantly less energy falls on the continents and oceans of this hemisphere of the planet, in which part of the rays fall at a small angle. In addition, the dark part of the day (night) increases significantly, with more than half of the corresponding hemisphere during this period being in the night at any given time. Thus, less energy is consumed per unit area and less heat is received. Even the sun sets completely in the area behind the Arctic Circle and there comes the polar night.