Why does winter happen

For those of us who live in the Northern Hemisphere where it's summer in July and winter in January, that seems backwards, doesn't it? That just goes to prove that Earth's distance from the Sun is not the cause of the seasons. What Causes the Seasons? The Short Answer:. Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays.

If you liked this, you may like: Bad space weather cancels pigeon races! It is Summer time in countries in the Southern Hemisphere. The north pole begins to move away from the Sun. The Sun rises lower in the sky so the days start getting shorter. When the Sun is at its mid-point in the sky, we reach the ' autumn equinox ', around 22 September. Day and night are both 12 hours long and its the beginning of autumn. The Earth continues on its path, and our north pole starts moving towards the Sun again.

The Sun moves upwards in our skies and the days continue getting longer. Again, we reach a midpoint when day and night are both 12 hours long. This is called the ' vernal or spring equinox ' and happens around 21 March. The Earth's movement around the sun causes the seasons, but it does not affect the temperatures during the seasons.

Many people believe that the temperature changes because the Earth is closer to the sun in summer and farther from the sun in winter. In fact, the Earth is farthest from the sun in July and is closest to the sun at the beginning of January! During the summer, the sun's rays hit the Earth at a steep angle because the sun is higher in the sky. The light does not spread out very much, thus increasing the amount of energy hitting any given spot.

They have about the same amount of daylight and darkness throughout the year. These places remain warm year-round. Near the Equator, regions typically have alternating rainy and dry seasons. Polar regions experience seasonal variation, although they are generally colder than other places on Earth. Near the poles, the amount of daylight changes dramatically between summer and winter.

In Barrow, Alaska, the northernmost city in the U. The city is in total darkness between mid-November and January. Seasons in Alaska Sometimes, seasons are determined by both natural and man-made activity. In the U. Ritu A ritu is a season in the traditional Hindu calendar, used in parts of India. There are six ritu: vasanta spring ; grishma summer ; varsha rainy or monsoon ; sharat autumn ; hemant pre-winter ; and shishira winter. Seasons can be natural, like hurricane season, which is the time of year when hurricanes are most likely to develop.

Seasons can also be artificially created, like hunting season, which is the time of year a community allows people to hunt certain wild animals. Meteorological Seasons Meteorologists, scientists who study the weather, divide each of the seasons into three whole months. Spring begins March 1, summer June 1, autumn September 1, and winter December 1.

Atlantic hurricane season runs from June 1 to November Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains. Also called the spring equinox. December 22 in the Northern Hemisphere, June 22 in the Southern Hemisphere longest night of the year and the beginning of winter. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.

The Rights Holder for media is the person or group credited. Caryl-Sue, National Geographic Society. Dunn, Margery G. For observers within a couple of degrees of the equator, the period from sunrise to sunset is always several minutes longer than the night. At higher latitudes in the Northern Hemisphere, the date of equal day and night occurs before the March equinox.

Daytime continues to be longer than nighttime until after the September equinox. In the Southern Hemisphere, the dates of equal day and night occur before the September equinox and after the March equinox.

The chart shown below shows the dates and times for the equinoxes and solstices through Times listed are in Eastern Time. Subtract one hour for Central Time. Source: U.

Naval Observatory. The answer is YES. However, you can stand an egg on end, with a large amount of patience, on any day of the year. This idea seems to pop up every year around the equinox. The thought that an egg can only stand on end on the spring equinox due to gravitational forces of the sun being aligned with the earth sounds like science, but it isn't. According to Chinese tradition, an egg can be made to stand on end at the precise moment winter ends and spring begins. But, the Chinese calendar had this transition occurring at a variable time each year, determined partly by the Chinese lunar month, usually in early February.

More recently, this thought became fixed to the time of the spring equinox. The underlying assumption relating to standing eggs on end is that there must exist some special gravitational balance. There are many forces acting on an egg when you try to stand it on end on a flat surface.

Some people think that the gravitational pull of the Sun becomes balanced with that of the Earth to allow for this phenomenon to occur. However, the Moon exerts a much stronger gravitational effect on the Earth than the Sun, dominating the ebb and flow of the ocean tides.