What are the causes of the seasons?

• The four divisions of the year (spring, summer, fall and winter) are marked by weather patterns and hours of daylight in a particular region.

• These patterns are a result of Earth’s 23.5° tilt of axis and its changing position as it orbits the Sun.

Earth's Axis is Tilted

• Earth spins around its axis once every 24 hours

• The axis is an imaginary line on which Earth rotates.

• This imaginary line intersects the surface of Earth at the North Pole and South Pole.

Earth's Axis is Tilted

• As Earth orbits around the Sun, it spins on its axis, which is tilted 23.5° relative to the plane of its orbit.

• Earth’s tilt of the axis points in the same direction in space but changes its position relative to the Sun depending on where it is located during its path of orbit.

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What does this have to do with seasons?

• During the month of June, the Northern Hemisphere and North Pole point toward the Sun.

• This causes temperature increases and changes in the atmosphere in the Northern Hemisphere that indicate the season of summer.

What does this have to do with seasons?

• During the month of December, the Southern hemisphere and South Pole point toward the Sun.

• This causes temperature increases and changes in the atmosphere in the Southern Hemisphere that indicate the season of summer.

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