What Are Perihelion and Aphelion?

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Sunset over Earth oceans as seen from the International Space Station.

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JSC/NASA

When Earth is Closest and Farthest from the Sun in 2024

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Earth reaches aphelion on July 5, 2024, and perihelion on January 4, 2025. Find out what these celestial terms mean and why they matter!

What Are Aphelion and Perihelion?

The terms perihelion and aphelion describe different points in our planet’s orbit of the Sun. This can also apply to other planets, comets, or bodies.    

  • Aphelion is the point of the Earth’s orbit that is farthest away from the Sun. It always happens in early July, about two weeks after the June solstice
  • Perihelion is the point of the Earth’s orbit that is nearest to the Sun. This always happens in early January, about two weeks after the December Solstice.

The words come from Ancient Greek, in which helios means “Sun,” apo means “far,” and peri means “close.”

(Did You Know: The point in the Moon’s orbit that is closest to the Earth is called the “perigee,” and the point farthest from the Earth is known as the “apogee.” Learn about perigee and apogee.)

Aphelion and Perihelion Dates for 2024 and 2025 

  • 2024 Perihelion: January 2, 2024 7:38 P.M.
  • 2024 Aphelion: July 5, 2024 1:06 A.M.
  • 2025 Perihelion: January 4, 2025 8:28 A.M.
  • 2025 Aphelion: July 3, 2025 3:54 P.M.

In 2024, Earth will be 91,404,095 miles away from the Sun at perihelion and 94,510,539 miles away from the Sun at aphelion. So, Earth is about 4,800,000 km (3,000,000 miles) farther from the Sun in July than in January.
 

the position of the earth and the sun at Aphelion and Perihelion

Are Aphelion and Perihelion What Cause the Seasons?

It’s not the distance from the Sun that causes our seasons. Seasons happen because the Earth’s axis is tilted at an angle. It’s because Earth orbits the Sun on a tilt that our planet gets more or less of the Sun’s direct rays at different times of the year. Read more about the reason for the seasons!

Aphelion and Perihelion on Mars

Though aphelion and perihelion are terms mostly used in reference to Earth since it’s our home planet, they are also relevant to other planets orbiting the Sun. Every planet has points in the orbits when they are farthest or closest away from their star.

For example, the planet Mars has an even more elliptical orbit than Earth. In comparison, Earth’s orbit seems almost circular; this almost-circular orbit may be why Earth’s climate is relatively stable.

Mars also has four seasons, but they are twice as long because it takes about two Earth years for Mars to go around the Sun. The southern hemisphere of Mars has warmer, shorter springs and summers than the north, as Mars is closest to the Sun, which is towards the end of southern spring. The southern winter is longer because Mars is farthest away from the Sun, moving more slowly in its elliptical orbit around the Sun.

For Mars, going from a colder winter to a warmer spring can be quite dramatic.

mars-orbit-year-seasons-winter-spring-summer-autumn-aphelion-perihelion_0_full_width.jpg
Image credit: JPL.NASA.gov

While Earth’s distance to the Sun varies throughout its orbit, with aphelion in July and perihelion in January, this variation isn’t the main driver of our seasons. The tilt of the Earth’s axis is the key factor. However, understanding aphelion and perihelion helps us appreciate the complexities of planetary motion and how even slight variations in orbit can influence climates.

Did you learn something new today? Or perhaps, do you understand aphelion and perihelion a bit better? 

About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann