Astronomy Essentials

Are the December solstice and January perihelion related?

December solstice and January perihelion: Brilliant sun with spikes, on black background, with Earth horizon below.
Are the December solstice and January perihelion related? After all, they’re both about our world’s relationship to the sun that binds it in orbit. Astronauts aboard the International Space Station took this image of Earth and the sun on May 9, 2021. Image via NASA.

December solstice, January perihelion

Earth comes closest to the sun on January 2-3, 2024. This event is called Earth’s perihelion. Meanwhile, the December solstice was December 21-23, 2023. The December solstice and January perihelion come close together in time. Are they related? No. It’s just a coincidence that they fall within about a two-week period each year.

The December solstice marked the sun’s southernmost path across our sky. At this solstice, Earth’s Southern Hemisphere is tilted most toward the sun. And so it’s summer now in that hemisphere. Meanwhile, the northern half of the globe is tilted most away from the sun at the December solstice. We typically say that winter begins at this solstice on our half of the globe.

Perihelion isn’t about Earth’s tilt. It’s about how near or far we are from the sun in orbit. The date of Earth’s perihelion drifts as the centuries pass. These two astronomical events are about two weeks apart for us now. But they were closer a few centuries ago. In fact, in the year 1246 CE, they happened on the same day.

The 2024 lunar calendars are here! Best New Year’s gifts in the universe! Check ’em out here.

Date of perihelion drifts

But, like all things in nature, the shape of Earth’s orbit isn’t static. Writing at, Aparna Kher explained:

Due to variations in the eccentricity of the Earth’s orbit, the dates when the Earth reaches its perihelion or aphelion are not fixed. Since 1246 CE, the perihelion and aphelion dates have drifted by a day every 58 years. In the short term, the dates can vary up to two days from one year to another.

So as the centuries continue to pass, the December solstice and January perihelion will drift even farther apart. Kher continued:

On the average, one revolution of the Earth relative to perihelion is about 25 minutes longer than one revolution relative to the December solstice. Perihelion advances one full calendar date about every 58 years.

Mathematicians and astronomers estimate that in 6430, over 4000 years from now, the perihelion will coincide with the March equinox.

Graphic showing sun at center, Earth on left during January perihelion and on right during July aphelion.
Earth-sun distance differences between the January perihelion (closest point) and July aphelion (farthest point). Earth is farthest from the sun when it is summer in the Northern Hemisphere. Illustration by Used with permission.

Bottom line: Earth’s December solstice and January perihelion are not related.

Earth closest to the sun on January 2-3, 2024

Everything you need to know: December solstice

Why does the New Year begin on January 1?

January 2, 2024
Astronomy Essentials

Like what you read?
Subscribe and receive daily news delivered to your inbox.

Your email address will only be used for EarthSky content. Privacy Policy
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

More from 

Deborah Byrd

View All