Why does the earliest sunset come before the shortest day?
Because the Sun’s time drifts against the clock. In early December, solar noon arrives a little later each day, which pushes sunsets later even as days shrink. Near 40°N the earliest sunset is around December 8.
Quick Answer
The earliest sunset of the year comes about two weeks before the winter solstice, and the latest sunrise comes about two weeks after it, because a solar day and a clock day aren’t quite the same length. The cause is the equation of time, the small difference between solar noon, when the Sun is highest, and clock noon. It exists because Earth’s axis is tilted and its orbit is an oval, so the true length of a solar day varies slightly through the year, and solar noon drifts by as much as about 16 minutes against the clock. In early December, solar noon arrives a little later by the clock each day. That nudges sunsets later even though days are still getting shorter, so the sunset time bottoms out first. At mid-northern latitudes, the earliest sunset falls between about December 4 and 12, near December 8 at 40°N, while the shortest day, December 21 in 2026, is still ahead. The latest sunrise doesn’t arrive until early January, around January 5 at 40°N.
By the Numbers
Key Facts
- Earliest sunset
- About two weeks before the winter solstice: near December 8 at 40°N
- Shortest day
- December 21, 2026, in the Northern Hemisphere
- Latest sunrise
- About two weeks after the solstice: near January 5 at 40°N
- The cause
- The equation of time: solar noon drifts against the clock
Timeline
- About Dec. 8
Earliest sunset of the year at 40°N.
- Dec. 21
Winter solstice: the day with the least daylight in the Northern Hemisphere.
- About Jan. 5
Latest sunrise of the year at 40°N.
The shortest day isn’t the earliest sunset
The December solstice has the least daylight of the year in the Northern Hemisphere, but that doesn’t make it the day with the earliest sunset or the latest sunrise. The earliest sunset comes about two weeks before the solstice, and the latest sunrise comes about two weeks after it. In between, the two effects add up: sunsets are already getting later while sunrises are still getting later, too, so the total daylight keeps shrinking until the solstice.
Why the clock and the Sun disagree
Our clocks assume every day is exactly 24 hours long. The Sun’s own day, from one solar noon to the next, varies slightly because Earth’s axis is tilted and its orbit is an oval. The result is called the equation of time, and it shifts solar noon by as much as about 16 minutes earlier or later than clock noon. In December, solar noon is moving later on the clock each day, which pulls sunsets later and sunrises later together.
It depends on where you live
The exact dates depend on your latitude. At mid-northern latitudes, the earliest sunset falls between about December 4 and 12, and the latest sunrise between about January 2 and 8. For your city’s exact dates, the U.S. Naval Observatory and timeanddate.com publish sunrise and sunset tables.
Myth vs. Fact
MythThe shortest day has the earliest sunset and the latest sunrise.
FactThe sunset is earliest about two weeks before the solstice, and the sunrise is latest about two weeks after it.
MythDays stop getting shorter when sunsets start getting later.
FactIn early December, sunsets begin to come later but sunrises keep coming later, so total daylight keeps shrinking until the solstice.
The Bottom Line
The earliest sunset comes about two weeks before the winter solstice because solar noon drifts against the clock, an effect called the equation of time. Near 40°N it falls around December 8, and the shortest day is December 21.
Sources & Further Reading
- U.S. Naval Observatory — Sunrise and Sunset Times Near the Solstices
- EarthSky — Your earliest sunset comes before the winter solstice
- Time and Date — Year’s Earliest Sunset Not on the Winter Solstice
- University of Connecticut CLEAR — Sunrise, Sunset and the Equation of Time
- EarthSky — When is my earliest sunset?