Orbital oddity: Later sunsets before winter solstice

Happy winter solstice week.


At 4:44 AM Wednesday the sun reaches the southernmost point on its annual trek.


Daylight starts getting ever-so-slightly-longer in the northern hemisphere where we live this week.

Later sunsets this week

If you blinked around 4:30 pm the past few days you may have missed it. But the sun started setting ever so slightly later across Minnesota. The elliptical nature of earth's orbit produces the oddity of later sunsets before Wednesday's winter solstice. Take a look at sunset times this week.

We gain 4 minutes on the sunset side of the day this week, and 10 minutes by month's end. Here's a good explanation of why sunset times move later even before the winter solstice from timeanddate.com.

Why Isn't the Year's Earliest Sunset on the Winter Solstice?

The Winter Solstice occurs around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere.

It 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. Astronomers call this difference the equation of time.

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 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.

Sun dogs: Sam Goertz

Enjoy the gradually increasing daylight in the evening in the next few weeks.

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