Science
How do the seasons work?
The seasons happen because Earth is tilted on its axis as it orbits the Sun. The tilt means each hemisphere leans toward the Sun for part of the year — getting more direct light and longer days (summer) — and away for the rest (winter).
See it in motion.
Watch a 2-minute animated lesson that shows exactly how the seasons works.
Step by step
- 1Earth's axis is tilted about 23.5 degrees relative to its orbit.
- 2As Earth orbits, each hemisphere tilts toward the Sun for half the year and away for the other half.
- 3Tilting toward the Sun brings more direct rays and longer days — summer.
- 4It's the angle of sunlight, not Earth's distance from the Sun, that drives the seasons.
- 5When it's summer in the north, it's winter in the south, and vice versa.
Frequently asked questions
- Are seasons caused by Earth's distance from the Sun?
- No — that's a common myth. Earth is actually slightly closer to the Sun in January. Seasons come from the axial tilt changing the angle and length of sunlight.
- Why are summer days longer?
- When your hemisphere tilts toward the Sun, the Sun's path across the sky is higher and longer, giving more daylight hours and more direct heating.
- Why are the seasons opposite in the southern hemisphere?
- When the northern hemisphere tilts toward the Sun (summer), the southern hemisphere tilts away (winter) — they're always in opposite phases.