Many people think summer is hot because Earth is closer to the Sun. But that is not the main reason for the seasons. The important reason is Earth’s tilted axis.
Earth moves around the Sun, but its axis keeps pointing in the same direction. During the year, different parts of Earth receive stronger sunlight. When the Northern Hemisphere tilts toward the Sun, it has summer.
When the Northern Hemisphere tilts away from the Sun, sunlight arrives at a lower angle. Then it gets winter. Earth’s tilt is the big reason we have seasons.
This angle also changes the length of days and the strength of sunlight.