January 3, 2026: Earth reaches perihelion as daylight slowly increases across the mid-northern latitudes. Learn how Earth’s orbit, astronomical units, and eccentricity affect seasons and sunlight.

by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:18 a.m. CST; Sunset, 4:32 p.m. CST. Times are calculated by the US Naval Observatory’s MICA computer program. Check local sources for sunrise and sunset times.
Daylight Lengthens
Daylight at the mid-northern latitudes is increasing. Today, at Chicago’s latitude, daylight spans 9 hours, 14 minutes. By month’s end, daylight increases by more than 45 minutes from today’s length, and sunset occurs at 5:05 p.m. Sunshine increases across the Northern Hemisphere, although the greatest daily gains occur at far northern latitudes. Sunrise remains at its latest time for another week before shifting earlier.
Earth at Perihelion

Earth is closest to the sun today (perihelion) at 11:16 a.m. Central Time. The separation is 0.9833 astronomical unit (A.U.). One astronomical unit equals Earth’s average distance from the sun, about 93 million miles. At aphelion next summer, Earth is 1.0166 A.U. from the sun.
The seasons result from Earth’s axial tilt, not from its distance from the sun. The solstice occurred about two weeks ago, maximizing direct sunlight across southern latitudes, while sunlight arrives at a lower angle and for shorter durations north of the equator.

Planets revolve around the sun in elliptical orbits rather than perfect circles. Earth’s orbit deviates from circular by 1.6%, producing a distance change of about 3 million miles between perihelion and aphelion. Mercury has the most eccentric planetary orbit in the solar system, differing from circular by 21%.
Measuring Distances
Astronomical units are used to describe distances within the solar system. This measurement simplifies comparisons among planets without relying on large numbers expressed in miles. For example, Jupiter’s average distance from the sun is 5.2 A.U., meaning it is 5.2 times farther from the sun than Earth.
Today marks perihelion, Earth’s closest point to the sun. Happy Perihelion Day!
LATEST ARTICLES
- 2026, April 14: Venus Dominates the Evening Sky with Sirius and Orion
April 14, 2026: Venus shines brightly after sunset while Sirius twinkles in the southwest. Orion stands between them as the spring sky shifts westward each evening. - 2026, April 13: Venus and Jupiter Shine After Sunset While Crescent Moon Appears Before Sunrise
April 13, 2026: Venus dominates the western sky after sunset while Jupiter shines higher in the sky. Before sunrise, find a waning crescent moon with earthshine in the east-southeast. - 2026, April 12-14: Waning Crescent Moon and Earthshine Before Sunrise
April 12-14, 2026: The waning crescent moon appears low in the southeast before sunrise. Watch it pass Deneb Algedi and photograph earthshine during the final mornings before new moon. - 2026, April 11: Spring Evening Sky – Spica, Hydra, Corvus, and Crater After Sunset
April 11, 2026: Two hours after sunset, find Spica low in the southeast with Hydra passing beneath it. Locate Corvus and Crater riding on the Snake’s back in the spring evening sky. - 2026, April 10: Spring Evening Sky – Leo, Cancer, and Hydra the Snake After Sunset
April 10, 2026: Leo stands high in the southern sky while faint Cancer and the Beehive Cluster appear nearby. Below them, Hydra the Snake stretches eastward toward Spica, marked by the solitary glow of Alphard.