The changing of the seasons in the Northern Hemisphere is primarily influenced by the tilt of Earth's axis and its orbit around the sun. Here are four key points that explain this phenomenon:
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Axial Tilt: Earth's axis is tilted at an angle of approximately 23.5 degrees relative to its orbital plane around the sun. This axial tilt is responsible for the varying intensity and duration of sunlight received at different latitudes throughout the year.
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Sunlight Distribution: As the Earth orbits the sun, the tilt causes different parts of the Northern Hemisphere to receive varying amounts of sunlight at different times of the year. During summer, the Northern Hemisphere is tilted toward the sun, leading to longer days and more direct sunlight, resulting in warmer temperatures. Conversely, during winter, the hemisphere is tilted away from the sun, leading to shorter days and less direct sunlight, resulting in cooler temperatures.
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Seasonal Transition: The position of Earth in its orbit results in intermediate seasons—spring and autumn—when the tilt is such that both hemispheres receive roughly equal sunlight. In spring, the days gradually become longer and warmer, while in autumn, the days shorten and temperatures cool.
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Equinoxes and Solstices: The solstices (around June 21 and December 21) mark the points in Earth's orbit where the Northern Hemisphere is at its maximum tilt toward or away from the sun, leading to the longest and shortest days, respectively. The equinoxes (around March 21 and September 23) occur when day and night are approximately equal in length, signifying the transition between the seasons.
These factors combined create the cyclical pattern of seasons experienced in the Northern Hemisphere, with distinct climatic differences throughout the year.