Four Seasons

A free interactive lesson on the four seasons — why Earth's 23.5° tilt creates spring, summer, autumn and winter as it orbits the Sun. Learn what changes in each season. Class 4 Science. Includes a quick quiz.

Class 4 ScienceClass 4 / Grade 4Ages 6–9
Lesson
🌸 Four Seasons
One year, four completely different worlds!🌸Springwarm & rainy☀️Summerhot & sunny🍂Autumncool & windy❄️Wintercold & frostySeasons happen because Earth tilts as it orbits the Sun!

Why is it hot in summer and cold in winter? Why do days get longer in summer and shorter in winter? The answer is not how close Earth is to the Sun — in fact, Earth is actually slightly closer to the Sun in winter in the Northern Hemisphere. The real cause of seasons is the way Earth is tilted on its axis. As Earth orbits the Sun over the course of a year, different parts of the planet receive more or less sunlight, creating the four seasons.

Why does Earth have seasons?

Earth is tilted at 23.5° on its axis. As it orbits the Sun over the course of a year, different hemispheres receive more or less direct sunlight. When the Northern Hemisphere tilts toward the Sun, it receives more intense sunlight for longer each day — that is summer. Six months later, it tilts away, receiving less sunlight — that is winter.

How do seasons affect living things?

Seasons drive fundamental changes in ecosystems:

  • Spring — flowers bloom, animals have young, birds migrate back
  • Summer — peak growth, insects abundant, fruits ripen
  • Autumn — leaves fall, animals store food, harvest time
  • Winter — many plants dormant, some animals hibernate, others migrate

Frequently asked questions

Are seasons opposite in the Southern Hemisphere?

Yes — when the Northern Hemisphere has summer (June-August), the Southern Hemisphere has winter, and vice versa. This is because the hemispheres tilt toward the Sun at opposite times of the year.

Why are days longer in summer?

In summer, the hemisphere is tilted toward the Sun, so the Sun appears to travel higher in the sky and takes longer to set. At the summer solstice (around June 21 in the north), the day is longest.

Do all places on Earth have four seasons?

No — near the equator, the climate stays warm year-round with little seasonal variation. Near the poles, seasons are more extreme with very long days in summer and very long nights in winter.

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