1. Seasons
Why do we have them?

2. Many places on Earth have 4 seasons:
Winter
Spring
Summer
Fall/ autumn
Sunlight hits the Earth most directly at the equator and at an angle near the poles
This is why it is warmer near the equator

3. Earth has seasons because it is tilted (23
Earth has seasons because it is tilted (23.5˚) as it revolves around the sun
Summer and winter are caused by Earth’s tilt
The change in seasons is NOT caused by a change in Earth’s distance from the sun
Earth is farthest from the sun when it is summer in the Northern hemisphere

4. Solstices June solstice: December solstice:
The north end of the Earth’s axis is tilted toward the sun
Northern hemisphere’s summer, Southern hemisphere’s winter
December solstice:
The south end of the Earth’s axis is tilted toward the sun
Southern hemisphere’s summer, Northern hemisphere’s winter

5. Equinoxes March (vernal or spring) and September (autumnal)
Neither end of the Earth’s axis is tilted toward the sun
Both hemispheres receive the same amount of energy

6. June Northern hemisphere has more hours of daylight than darkness
Summer in the Northern hemisphere
Opposite for the Southern hemisphere

7. December Northern hemisphere has fewer hours of daylight
Winter in the Northern hemisphere

8. Solstice and Equinox Dates
June 21- summer solstice for Northern hemisphere
December 21 – winter solstice for the Northern hemisphere
March 21- spring (vernal) equinox for Northern hemisphere; 12 hrs of day and night
September Autumnal equinox for Northern hemisphere; 12 hrs of day and night
Equinox = “Equal night”