Later sunsets begin this week in Minnesota

Here’s a ray of hopeful news in this darkest month of the year in Minnesota. The sun set at 4:31 p.m. this week in the Twin Cities. It begins to creep ever so slowly later into the evening as we move later into December.

By New Year’s Eve, the sun will set a full 10 minutes later at 4:41 p.m.!

Sunset times begin to move later into the evening before the solstice on Dec. 21.

One reason is that Earth’s orbit is an ellipse and not a circle. That plays with the sunset times around the solstice. That’s why the earliest sunset of the year is not on the winter solstice.

Here’s more detail from timeanddate.com:

Winter solstice is the shortest day of the year in terms of daylight, but it does not have the latest sunrise nor the earliest sunset of the year.

This is because of a discrepancy between our modern-day timekeeping methods and how time is measured using the Sun, known as the equation of time.

Earliest Sunset a Few Days Before

If you look at the sunrise and sunset times for any city in the Northern Hemisphere around the December Solstice, you will notice that the earliest sunset occurs a few days before the solstice and the latest sunrise happens a few days after the solstice.

This is also true for locations in the the Southern Hemisphere. There, the year's earliest sunset happens a few days before, and the year's latest sunrise occurs a few days after the winter solstice in June.

Comparing Cities

Let’s take the example of New York City in the Northern Hemisphere and Sydney in the Southern Hemisphere. As you can see in the table, the latest sunrises and the earliest sunsets in the two cities do not occur on the day of the winter solstice.

City Winter Solstice Date Latest Sunrise Date Earliest Sunset Date

New York

(40°43' North) December 21, 2024

04:20 (4:20 am) EST January 3 and 4, 2025

07:20 (7:20 am) EST December 7, 2024

16:28 (4:28 pm) EST

Sydney

(33°8' South) June 21, 2024

06:50 (6:50 am) AEST June 29 and 30, 2024

07:01 (7:01 am) AEST June 11 and 12, 2024

16:52 (4:52 pm) AEST

This can be explained by two factors: the equation of time and a location's latitude.

Equation of Time = Apparent Solar Time – Mean Solar Time

The equation of time is the difference between time measured using a sundial, also known as true or apparent solar time, and time measured using a clock, also known as mean solar time. It is often pictorially represented by a figure 8, which is called an analemma.

Most clocks run on the idea that a day is exactly 24 hours. Technically, a day is the duration between one solar noon, the time of the day when the Sun is at the highest point in the sky, to the next.

In the Twin Cities, the earliest sunset is 4:31 p.m. and occurs around Dec. 9.

So even in these darkest days of winter, I take it as a great sign that evening daylight begins to increase. On clear days by the end of the month, it’s light in the western sky until at least 5 p.m. with civil twilight.

So even though the days grow colder, there’s more light at the end of the wintry tunnel each day.