Every year, Earth reaches a specific point in its orbit known as aphelion—the moment when our planet is at its maximum distance from the Sun.
In 2025, this event occurred on Thursday, July 3.
Aphelion is an astronomical term that refers to the point in a celestial body's orbit when it is farthest from the star it orbits. While commonly associated with Earth, the concept also applies to comets, asteroids, and other planets.
How Far Is Earth from the Sun at Aphelion?
On July 3, 2025, at precisely 21:54:43 Paris time, Earth will be approximately 152,087,737 kilometers (about 1.02 astronomical units) from the Sun, according to the Paris Observatory's Space-Time Reference Laboratory.
One astronomical unit (AU) is the average distance between the Earth and the Sun—roughly 150 million kilometers.
Aphelion vs. Perihelion: Two Sides of the Orbit
The opposite of aphelion is perihelion, the point at which Earth is closest to the Sun. The last perihelion occurred on January 4, 2024.
The date of aphelion isn't fixed. Between 2019 and 2030, it fluctuates between July 3 and July 6, influenced by several factors—including Earth’s shared motion with the Moon around a common center of mass (called the barycenter) and the Moon’s orbital phase and position near perigee or apogee.
How Aphelion Affects the Seasons
Surprisingly, seasons are not determined by how close Earth is to the Sun, but rather by the tilt of Earth’s axis. However, aphelion does influence the length of the seasons.
The Paris Observatory explains that seasonal durations are uneven. If the positions of aphelion and perihelion were constant, seasons would be equal in length. But because Earth's orbital speed varies, with Earth moving fastest at perihelion and slowest at aphelion, the result is a shorter winter and a longer summer in the Northern Hemisphere.
In other words, during early January, when Earth is closest to the Sun, it moves more quickly through space, making winter the shortest season. In contrast, around early July, Earth is farthest from the Sun, its orbital speed is at a minimum, and summer becomes the longest season.
A Hidden Celestial Reminder
Though aphelion may be invisible to the casual observer, it serves as a reminder of the complex mechanics governing Earth's journey through the solar system. It reveals how subtle cosmic forces shape our experience of time and nature, highlighting the interconnectedness between astronomy and everyday life.
