Why the Shortest Day Is Not the Day With the Earliest Sunset or Latest Sunrise
Mia Chow · · Updated · Estimated reading time: 6 minutes
Many people assume that the shortest day of the year (winter solstice), the earliest sunset, and the latest sunrise all happen on the same day. It makes sense, right? But the reality is a little bit more complicated than that.
In the Northern Hemisphere, the winter solstice, the shortest day of the year, falls around December 21-22. However, at mid-northern latitudes the earliest sunset occurs around December 4–12, and the latest sunrise happens around January 2–8, and the further south you go, the further apart those dates drift. But why?
First, Let’s Talk About the Winter Solstice
The winter solstice is the day when the North Pole is tilted the farthest away from the Sun. On this day, the Sun follows its shortest arc across the sky, giving us the least amount of daylight in the Northern Hemisphere.
But here’s the thing, the solstice isn’t about sunrise or sunset times—it’s about the Sun’s position in the sky.
The Role of Earth’s Tilt and Orbit
Earth’s 23.5-degree axial tilt and its elliptical (not perfectly circular) orbit around the Sun are key players in this drama.
Axial Tilt
This tilt gives us seasons, as different parts of Earth receive varying amounts of sunlight throughout the year.
Elliptical Orbit
Earth doesn’t orbit the Sun at a constant speed. It moves faster when it’s closer to the Sun (perihelion, in early January) and slower when it’s farther away (aphelion, in early July). This uneven speed affects the timing of solar noon—the moment when the Sun is highest in the sky.
When you combine these two factors—the changing speed of Earth in its orbit and the tilt of its axis—you get what astronomers call...
The Equation of Time
Here’s where it gets even more interesting. The "equation of time" is a concept that explains discrepancies between solar time (based on the Sun’s position) and clock time (which assumes the Sun moves at a constant rate and divides the day into equal 24-hour segments). This difference can add up to about 16 minutes throughout the year.
The tilt and elliptical orbit cause solar noon, the moment when the Sun reaches its highest point in the sky, to shift slightly day by day.
During December, solar noon gradually shifts later relative to our clock time. At the same time, the day keeps getting shorter until the solstice. Those two changes pull sunrise and sunset in opposite directions, and which one is winning on any given day is what sets the dates.
Sunrise and sunset sit either side of solar noon, half a day away in each direction:
sunset = solar noon + half the length of the day
sunrise = solar noon − half the length of the day
A sunset time can therefore move for only two reasons: solar noon has shifted, or the day has changed length. And because of the plus and the minus, that same pair of numbers cancels out at one end of the day and adds up at the other.
Earliest Sunset
Take New York on December 1. Solar noon arrives about 23 seconds later than the day before, and the day is about 80 seconds shorter, which means 40 seconds lopped off each end. For sunset the two work against each other: 23 seconds later, 40 seconds earlier, so the Sun sets about 17 seconds earlier than yesterday. The shortening day is winning, and sunsets keep creeping earlier.
But as the solstice approaches, the length of the day flattens out. That is precisely what a solstice is: the turning point where the day stops getting shorter. The daily loss falls to 32 seconds per end on December 5, 29 on December 7, 14 on December 15, and practically zero on the solstice itself. The solar noon delay, on the other hand, does not flatten out at all: it holds steady at 23–30 seconds a day right through December.
So there is one day when the two are the same size and cancel out, and the Sun sets at almost exactly the same clock time as the day before. That day is the earliest sunset: December 7 in New York, a full 14 days before the solstice. From then on the noon delay is the bigger of the two numbers, and sunsets start getting later again even though the days are still getting shorter.
That is all "balancing out" means, and the distinction matters: the days do not stop getting shorter, they keep shortening right up to the solstice. What becomes equal is the size of the two daily changes, pointing in opposite directions.
| Date | Solar noon | Length of day | Sunset | vs. day before |
|---|---|---|---|---|
| December 1 | 11:45:07 am | 9h 31m 37s | 4:30:55 pm | −17 s |
| December 5 | 11:46:42 am | 9h 27m 00s | 4:30:12 pm | −7 s |
| December 7 | 11:47:33 am | 9h 25m 02s | 4:30:04 pm | −3 s ← earliest sunset |
| December 15 | 11:51:14 am | 9h 19m 40s | 4:31:04 pm | +15 s |
| December 21 | 11:54:11 am | 9h 18m 24s | 4:33:23 pm | +29 s ← solstice |
New York, December 2026. Read the last two columns together: the day keeps getting shorter all the way down the table, and yet the sunset turns around a fortnight earlier.
Latest Sunrise
At the other end of the day the minus sign flips everything, and the two effects add up instead of cancelling. Before the solstice, solar noon is later and the morning end of the day is being eaten into: 23 + 40 = about 63 seconds later every day. That is why in early December the sunrise races forward by a full minute a day while the sunset is barely moving at all.
After the solstice the day starts growing again, which pulls sunrise back towards the earlier hours, but solar noon is still drifting later, and it keeps doing that until around February 11. The latest sunrise is the day the two finally match: January 4 in New York, at 7:18:34 am. In the Southern Hemisphere the same thing happens around the June solstice, with the earliest sunset in early June and the latest sunrise in late June or early July.
Why the Date Depends on Your Latitude
The solar noon drift is a global affair. It depends on the date, not on where you are, so it is the same ~30 seconds a day everywhere on Earth. What changes with latitude is the other number: how fast the day is shortening. The faster it shortens, the longer it takes for the noon drift to overtake it, and the closer to the solstice the earliest sunset falls.
- Oslo (60°N): December 16
- Berlin (53°N): December 13
- New York (41°N): December 7
- Lisbon (39°N): December 7
- Mexico City (19°N): November 25
- Singapore (1°N): November 5
Oslo is losing 3 minutes and 17 seconds of daylight a day on December 1, so up there the day length keeps winning almost until the solstice. Near the equator the day length barely changes at all, the noon drift takes over almost immediately, and the gap between the earliest sunset and the shortest day stretches to nearly two months. That is also why you will see slightly different dates quoted in different places: there is no single date, only the one for your latitude.
This is also why sunrise and sunset times don't change at the same rate throughout the year.
Key Takeaways
The shortest day of the year, the winter solstice, isn’t the day with the earliest sunset or the latest sunrise because of two key factors: the Sun’s height in the sky and the timing of solar noon (when the Sun is highest) relative to clock time.
In December, solar noon gradually shifts later each day compared to clock noon. This delay affects both sunrise and sunset times. At the same time, the Sun’s arc across the sky gets shorter, reaching its lowest point on the solstice.
These combined effects mean the earliest sunset happens before the solstice, while the latest sunrise occurs after. The shortest day only marks the lowest Sun arc, not the extremes of sunrise or sunset.
This question pops up every December without fail, and we totally get it, it’s not the easiest concept to wrap your head around. But hopefully, this explanation helps make it all a little clearer!