June 21, 2026, marks the first day of summer in the Northern Hemisphere. But what actually causes the seasons to change throughout the year? Many people believe the seasons occur because Earth moves closer to or farther from the Sun. In reality, that’s not the reason at all.
Frequently Asked Questions About the Seasons
- What causes the seasons to change?
- The seasons are caused by Earth’s axial tilt, not by Earth’s distance from the Sun.
- Earth is tilted about 23.5 degrees relative to its orbit around the Sun. As our planet travels around the Sun each year, different regions receive varying amounts of sunlight and daylight, creating the seasons.
How does Earth’s tilt create summer and winter?
- Because Earth is tilted, the angle and duration of sunlight change throughout the year.
During Summer:
- Our Northern hemisphere is tilted toward the Sun.
- Sunlight strikes the surface more directly.
- Days are longer.
- Temperatures are warmer.
During Winter:
- Our hemisphere is tilted away from the Sun.
- Sunlight arrives at a lower angle.
- The Sun’s energy is spread over a larger area.
- Days are shorter.
- Temperatures are cooler.
Why are the seasons opposite in the Northern and Southern Hemispheres?
- When one hemisphere is tilted toward the Sun, the other is tilted away.
For example:
- Northern Hemisphere tilted toward the Sun – Summer in the north
- Northern Hemisphere tilted away from the Sun – Winter in the north
- This means that when it’s summer in the United States and Canada, it’s winter in countries such as Australia and New Zealand.
So when summer begins on June 21, 2026, remember it’s not because Earth is closer to the Sun—it’s because the Northern Hemisphere is tilted toward it.
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