1. Seasons on Earth Two reasons the Earth has seasons: 23.5 degree tilt
Revolution around sun

2. Seasons on Earth
Most places have four seasons: winter, spring, summer, and autumn.

3. Earth’s Tilted Axis
Earth has seasons because its axis is tilted as it move around the sun.

4. Earth in June
The north end of Earth’s axis is tilted toward the sun. It is summer in the Northern Hemisphere and winter in the Southern Hemisphere.

5. Earth in December
The south end of Earth’s axis is tilted toward the sun. It is summer in the Southern Hemisphere and winter in the Northern Hemisphere.

6. Both in June and December
Summer solstice - longest day of the year (June 21).
Winter solstice - shortest day of the year (December 21).
Both of the these are in the Northern Hemisphere and the opposite in the Southern Hemisphere.

7. Earth in March & September
Neither hemisphere is tilted toward or away from the sun. So the days and nights are in a equinox which is equal.

8. Earth in March and September
Vernal equinox, or spring equinox, occurs around March 21 and is the first day of spring.
Autumnal equinox, or fall equinox, occurs around September 23 and is the first day of fall.