Why Do We Have Seasons?

What You'll Learn

• The Earth is tilted on its axis at 23.5 degrees
• As Earth orbits the Sun, the tilt means different parts get more or less sunlight
• When your part of Earth tilts toward the Sun, it's summer
• When your part tilts away from the Sun, it's winter
• The Earth's tilt — NOT distance from the Sun — causes seasons

Words to Know

Season

A time of year with certain weather

"Winter is the coldest season."

Tilt

To lean to one side

"Earth is tilted 23 degrees."

Axis

An imaginary line through Earth's middle

"Earth spins on its axis."

Orbit

The path Earth takes around the Sun

"Earth's orbit takes one year."

Check What You Learned

Fun Facts

• Earth's axis is tilted at 23.5 degrees from perpendicular

  Source: NASA

• Earth orbits the Sun once per year (~365.25 days)

  Source: NASA

• When a hemisphere tilts toward the Sun, it receives more direct sunlight = summer

  Source: NOAA

• When a hemisphere tilts away, sunlight hits at an angle, spreading out = winter

  Source: NOAA

• Seasons are NOT caused by distance from the Sun — Earth is closest to the Sun in January (perihelion)

  Source: NASA

• Northern and Southern Hemispheres have opposite seasons

  Source: NOAA