Summer, bring it on! After the summer solstice (June 20, 2024), we start to lose daylight. How fast? Bob Berman talks about solstices and sunsets鈥攁nd finding out how rapidly the times change where you live.
First, here is a refresher: The summer solstice is the first day of summer, according to astronomy. The word solstice comes from the Latin words 鈥渟un鈥 and 鈥渟toppage.鈥 It makes sense: The Sun stops moving North that day. The Sun’s most direct rays reach the maximum northernmost position.
The Sun stands directly over the Tropic of Cancer, the most northerly Earthly place that ever sees an overhead Sun. Interestingly, 鈥楥ancer鈥 isn鈥檛 really appropriate. True, it was the constellation the Sun hovered in front of on the day of the solstice, back when early observers started paying attention to such things thousands of years ago. However, since then, Earth鈥檚 axis has wobbled around like a slowing top, which made the place the Sun occupies on June 20 change first to Gemini and then, in 1989, to Taurus the Bull, where it鈥檒l remain for the next half millennium. Bottom line: The Sun should be labeled as hovering over the Tropic of Taurus!
No matter, the basic truth stands: Nowhere in the mainland US or Europe does anyone live in the tropic of whatever. So, no American except Hawaiians, who live south of that tropic line, can ever see the Sun straight overhead.
How Quickly We Lose Daylight
Ask friends what happens, and they鈥檙e likely to get it right, mostly. Longest day of the year 鈥 check. The shortest night of the year 鈥 check.
- On the solstice, sunrise in Seattle, Washington, was at 5:09 a.m., and sunset was at 9:12 p.m. Daylight is 16 hours, 3 minutes!
After the solstice, the days will get progressively shorter throughout the summer into the fall. Yes, it starts to get dark earlier.
- Take Seattle again. By the fall equinox, or the first day of fall, on Sept. 22, the sunrise is expected at 6:54 a.m., and sunset is expected to set at 7:09 p.m. Daylight is 12 hours, 14 minutes.
Take a southern city; notice the difference!
- On the solstice, the sunrise in Miami, Florida was at 6:28 a.m. and the sunset was at 8:16 p.m. Daylight hours totaled 13 hours, 27 minutes.
- On the fall equinox, sunrise is 7:08, and sunset is 7:18 p.m. Daylight is 12 hours, 10 minutes.
Pop your zip code into the 蜜桃恋人 Sunrise/Set Calculator to see how the sunrise and sunset times change where you live (as well as your day length).
We Lose Daylight Faster as We Near Equinox
Here’s something else interesting: After the solstice, we’ll start losing daylight, but the pace will happen much more slowly in the summer and start to speed up as we reach the autumnal equinox.
Sunrise and sunset times hold fairly steady for the two weeks, bookending the solstice. But after that, sunrise times start to get later in the morning again very subtly, by only one minute or so. And sunsets after the solstice slowly become earlier in the evening. As the summer marches on, you’ll notice the length of the day starts to decrease more rapidly.
- Take a Midwestern city this time. Chicago enjoys 15 hours and 16 minutes on the solstice (June 20). About 10 days later (July 1), daylight is 15 hours, 13 minutes (-3 minutes). Go another 10 days (July 11), and daylight is 15 hours, 4 minutes (-9 minutes more).
Why does the speed change? The Earth鈥檚 axis is tilted by about 23.5 degrees relative to its orbital plane, so the path of the Sun through the daytime sky goes from nearly perpendicular and directly overhead near the Equinoxes to far from perpendicular and far from overhead during the Solstices as the Earth orbits the Sun. You can see this effect by watching how much the angle of the sunrise changes during each period! Near the solstice, time seems to move more slowly than near the equinox.
One more Sun fact that few people know: As the sun sets, does it drop straight down, down and to the left, or down to the right? Most get this wrong. A century ago, everyone would have correctly picked the latter choice (to the right) in a heartbeat.
Finally, the nicest fact may simply be that the Sun is now so wonderfully high. From a typical latitude, like that of Denver or Philadelphia, it stands 72掳 up at 1 PM and won’t change much in the next few weeks. Look how short your midday shadow is! You鈥檒l be Punxsutawney Phil in reverse, marveling at your mostly missing shadow.
