What causes the four seasons?

Seasons are caused by Earth's 23.5-degree tilt on its axis. As Earth orbits the sun, different hemispheres tilt toward or away from the sun. The hemisphere tilted toward the sun receives more direct sunlight and experiences summer, while the opposite hemisphere experiences winter [citation:3][citation:7].

Why are seasons opposite in different hemispheres?

When the Northern Hemisphere tilts toward the sun (summer), the Southern Hemisphere tilts away (winter). This creates opposite seasons. That's why December is cold in New York but warm in Sydney—they're experiencing opposite seasons simultaneously.

What are the characteristics of each season?

Spring brings warming temperatures, blooming plants, and longer days. Summer features the warmest weather and longest daylight. Fall shows cooling temperatures, changing leaf colors, and harvest time. Winter brings the coldest temperatures and, in many places, snow and ice [citation:3].

The Four Seasons

Exploring spring, summer, fall, and winter—the annual cycle of weather changes that shapes our environment and activities.

The Four Seasons

Exploring spring, summer, fall, and winter—the annual cycle of weather changes that shapes our environment and activities.

The four seasons—spring, summer, fall, and winter—create the rhythm of our year. Each brings distinct weather patterns, changes in nature, and shifts in how we live. Understanding seasons helps us appreciate the natural cycles that surround us [citation:3].

Seasons are caused by Earth's tilt on its axis as it orbits the sun. When the Northern Hemisphere tilts toward the sun, it experiences summer with longer days and more direct sunlight. When it tilts away, winter arrives with shorter days and indirect light. This tilt, not distance from the sun, creates our seasonal changes [citation:3][citation:7].

Each season has unique characteristics. Spring brings warming temperatures and new growth. Summer offers the warmest days and longest daylight. Fall features cooling weather and changing leaf colors. Winter brings the coldest temperatures and, in many regions, snow and ice.

Whether you're curious about nature, planning seasonal activities, or simply want to understand the world around you better, this guide explains the fascinating cycle of the four seasons.

Time Tools

Weather — Explore weather patterns and forecasts that change with the seasons throughout the year.
Calendar — Track seasonal changes and mark the first day of each season with our digital calendar.
Planner — Plan seasonal activities, from spring gardening to winter holidays, with our planner.

Seasons Questions

What causes the four seasons?: Seasons are caused by Earth's 23.5-degree tilt on its axis. As Earth orbits the sun, different hemispheres tilt toward or away from the sun. The hemisphere tilted toward the sun receives more direct sunlight and experiences summer, while the opposite hemisphere experiences winter [citation:3][citation:7].
Why are seasons opposite in different hemispheres?: When the Northern Hemisphere tilts toward the sun (summer), the Southern Hemisphere tilts away (winter). This creates opposite seasons. That's why December is cold in New York but warm in Sydney—they're experiencing opposite seasons simultaneously.
What are the characteristics of each season?: Spring brings warming temperatures, blooming plants, and longer days. Summer features the warmest weather and longest daylight. Fall shows cooling temperatures, changing leaf colors, and harvest time. Winter brings the coldest temperatures and, in many places, snow and ice [citation:3].

Spring: Season of Renewal

Spring arrives as temperatures warm and plants emerge from winter dormancy. Days grow longer, trees bud, and flowers bloom. In many cultures, spring represents renewal and new beginnings. Weather becomes more variable, with increasing rainfall in many regions. Animals emerge from hibernation, and migratory birds return. Spring equinox marks the astronomical beginning of spring, when day and night are nearly equal in length [citation:3][citation:4].

Summer: Warmest Days

Summer brings the year's warmest temperatures and longest days. The sun follows its highest path across the sky, delivering the most direct sunlight. Plants grow rapidly, and many crops reach harvest. People spend more time outdoors, enjoying vacations and warm-weather activities. Summer solstice, around June 21 in the Northern Hemisphere, is the longest day of the year. Thunderstorms are common in many regions during summer afternoons [citation:4].

Fall: Season of Change

Fall, also called autumn, brings cooling temperatures and dramatic changes in nature. Days grow shorter, and plants prepare for winter dormancy. Deciduous trees display brilliant colors—reds, oranges, and yellows—before shedding their leaves. Many crops are harvested during fall. Animals gather food and prepare for winter. Fall equinox marks equal day and night before the Northern Hemisphere begins tilting away from the sun [citation:4].

Winter: Coldest Season

Winter brings the coldest temperatures and, in many regions, snow and ice. Days are shortest, with the sun low in the sky. Many plants are dormant, and some animals hibernate or migrate to warmer areas. Winter solstice, around December 21 in the Northern Hemisphere, is the shortest day of the year. Despite the cold, winter offers unique activities—skiing, ice skating, and cozy gatherings. Many cultures celebrate holidays during winter, bringing light to the darkest season [citation:4].