The March equinox is coming up fast. It’ll come at 14:46 UTC (9:46 a.m. CDT) on March 20, 2026. And here’s a little-known equinox phenomenon: the sun sets faster around the time of an equinox. The fastest sunrises happen at or near the equinoxes, too. On the other hand, the slowest sunsets (and sunrises) happen around the solstices. It’s true whether you live in Earth’s Northern or Southern Hemisphere.
By the way, when we say sunset here, we’re talking about the actual number of minutes it takes for the body of the sun to sink below the western horizon.
So why does it happen? Why does the body of the sun fall below the horizon so quickly at equinox time? It’s because, at every equinox, the sun rises due east and sets due west. That means – on the day of an equinox – the setting sun hits the horizon at its steepest possible angle.
The equinox is an event that takes place in Earth’s orbit around the sun. Image via National Weather Service/ weather.gov.
Year’s slowest sunsets and sunrises
Meanwhile, at a solstice, the sun is setting farthest north or farthest south of due west. And, the farther the sun sets from due west along the horizon, the shallower the angle of the setting sun. So that means a longer duration for sunset at the solstices.
Also, the sunset duration varies by latitude. Farther north or south on the Earth’s globe, the duration of sunset lasts longer. So, closer to the equator, the duration is shorter. But let’s just consider one latitude, 40 degrees north, the latitude of Denver or Philadelphia in the United States; parts of Spain; and Beijing, China.
At that latitude, on the day of equinox, the sun sets in about 2 3/4 minutes.
On the other hand, the solstice sun sets in roughly 3 1/4 minutes at 40 degrees latitude.
Sunset and sunrise images from the EarthSky community
View at EarthSky Community Photos. | Peter Lowenstein captured these images and wrote: “Equinox sunsets before and after equinox sunrise on September 23, 2023. The instant of the Southern Hemisphere spring equinox in 2023 was at 6:50 UTC on September 23. This means it was possible to record 2 equinox sunsets, one on the 22nd a few hours before, and another a few hours after the equinox sunrise on the 23rd.” Thank you, Peter!View at EarthSky Community Photos. | Teresa Molinaro captured this image on September 28, 2024, in Italy. Teresa wrote: “A very intense dawn occurred on the morning of late September; and in the seaside village everything was silent.” Thank you, Teresa!
Bottom line: The fastest sunsets and sunrises of the year are happening now, around the time of the March equinox.
Bruce McClure served as lead writer for EarthSky's popular Tonight pages from 2004 to 2021, when he opted for a much-deserved retirement. You can still find many articles at EarthSky.org that were originally written by Bruce, and which the EarthSky editors still update regularly. Bruce is a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also wrote and hosted public astronomy programs and planetarium programs in and around his home in upstate New York. Bruce he loves cycles of all kinds! You can still find many articles at EarthSky with Bruce's name on them, exploring the various, intricate cycles of the sky.
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