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What is a season

01:00 Mon 09th Apr 2001 |

A.� The year is divided equally into four of them, spring, summer, autumn, and winter. Each season lasts for 3 months and represents changes in temperature, weather and the length of daylight.

Q.� What's the difference between climatic and astronomical seasons

A.� Climatic seasons are based on temperature and rainfall changes, whereas astronomical seasons are based on the tilt of the Earth in relation to the Sun, obviously the two are inextricably linked. Astronomical seasons are the ones by which we determine our calendar: for example summer begins on June 21st in the northern hemisphere, when the North Pole is titled toward the Sun.

Q.� What causes seasonality

A.� The seasons are caused by the Earth's axial tilt in relation to the Sun. Without this tilt it would always be spring or autumn. As the Earth moves around the Sun changes occur in the amount of sunlight received.

Q.� Does everywhere get the same season at the same time

A.� No, the beginning and end of the climatic seasons vary from these dates from place to place. For example the climatic seasons in the northern hemisphere differ by about six months from those in the southern hemisphere, one has winter while then other has summer.

Q.� Why is there no noticeable shift in weather type from, for example, the last day of spring and the first day of summer

A.� The temperature and weather do not change instantly when the Earth changes position in relation to the Sun. The warmest and coldest weather generally occurs several weeks after the beginning of the summer and winter astronomical seasons. Heat that has been retained by the oceans plays an important role in producing this delayed response.

Q.� Does everywhere have seasons

A.� No. Some regions do not have all four climatic seasons. In parts of the tropics, for example, temperatures change little. But the amount of rainfall varies greatly, so that these regions have a wet season and a dry season.

The Polar Regions, on the other hand, have a light season and a dark season. In these parts of the world, the Sun shines almost all the time in summer and almost never during the winter.

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by Lisa Cardy

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