Sun, from which the earth was removed almost 150 million. Km, the planet is sending a lot of heat. Through solar heat and there is life on Earth. But reaching our planet heat in its various areas of unevenly distributed.
Heat flows differently in the course of the year. In winter everywhere cooler than summer. And there is so because the Earth's axis, t. E. An imaginary line connecting the North and South poles, is tilted to the plane of Earth's equator at an angle of 66.3. Therefore, the Earth rotates around the sun, facing it with either the North Pole or the South. The slope of the sunlight falling on the earth's surface, changes during the year: in winter it is, less in summer. And what sheer rays, the more they bring with them energy. Not by chance the Greek word "climate" means in translation "slope".
When the Earth turns away from the sun in the northern hemisphere winter comes, we can see that everything below the sun disk above the horizon, and its rays are becoming flatter, less hot. Only at the equator, and near it, where throughout the year the day is night, midday height of the sun above the horizon does not change. Therefore, there is a year-round temperature is almost constant. This is a land of "eternal summer", where there is no time of the year. In the mid-latitudes of the northern hemisphere year is divided into two main seasons, the opposite nature: summer and winter. The difference in temperature between 20-30 C, and removed from the ocean (continental) areas - even more, such as Siberia, and 50, while in other areas - to 100, that is in summer - plus 40, winter - negative 60.
The boundary of the winter and spring - the spring equinox on March 21 when the day is night. The same thing happens on the day of the autumnal equinox on September 23 when the summer ends. June 22 - the summer solstice the sun reaches its maximum height for a given latitude; December 22 - the day of the winter (very low over the horizon) solstice. In the Southern Hemisphere - all exactly the opposite, because when north of the equator - the winter to the south - the summer, and vice versa. But due to the fact that the southern hemisphere is mainly occupied by the ocean, in the summer it is cooler than in the north, and warm in winter. The duration and the nature of the seasons in different regions of our country are very different. It depends not only on the latitude and altitude but also on the laws of motion of air in the atmosphere. Warm, cold, wet or dry air is often distributed quite there "out of season". We are not surprised to learn that the New Year in Moscow, the rain, and a thousand kilometers to the south, in the Krasnodar region, there are frosts. So it can happen when the middle of the winter Atlantic winds bring warm air to where should be frost and icy north gush air where winters are usually mild.
Effect of warm North Atlantic Gulf Stream affects almost the entire territory of our country, and the degree of this influence depends on the weather in the winter. Polar Murmansk does not freeze, and is located in the far south of its winter Vladivostok at Siberian frosty. That's remoteness from the Atlantic due solely to a cold winter in Eastern Siberia, where the Ojmjakon - "cold pole" of the northern hemisphere. Winter frosts here are down to minus 60 ° C or more. In accordance with the seasons to rebuild the entire flora and fauna in winter life fades. Trees shed their leaves, and their growth is interrupted. Annual grasses die. Many animals fall into hibernation for the winter, the birds go to a warmer climate. Fields and forests wraps snow, which protects all life that is left in the soil (bacteria, seeds, tubers perennials, shoots of winter crops), from the damaging frost. Snow protects itself and the soil from deep freezing. And besides, the moisture accumulates, so the right plants in the spring. ...
If earth's axis were not tilted to the orbit would be very different climates on the planet: they would, in fact, only two - pole (eternal winter) and equatorial (eternal summer) and they gradually shifted to each other. In the same climate conditions are not so varied would be life on Earth.