After the Summer Solstice, How Fast are We Losing Daylight?
Yes, it gets dark earlier after the solstice.
Summer, bring it on! After the summer solstice (June 21), we start to lose daylight. How fast? Bob Berman talks solstices and sunsets—and you can find out how rapidly the times change where you live.
First a refresher: The summer solstice is the first day of summer, according to astronomy. The word solstice comes from the two Latin words “sun” and “stoppage.” 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, ‘Cancer’ isn’t 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’s axis has wobbled around like a slowing top, which made the place the Sun occupies on June 21 change first to Gemini, and then, in 1989, to Taurus the Bull, where it’ll remain for the next half millennium. Bottom line: Wednesday’s 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 on 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’re likely to get it right, mostly. Longest day of the year – check. Shortest night of the year – 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 Almanac 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 day starts to decrease more rapidly.
Take a Midwestern city this time. Chicago enjoys 15 hours, 16 minutes on the solstice (June 21). 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’s 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 is setting, 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° up at 1 PM and won’t change much in the next few weeks. Look how short your midday shadow is! You’ll be Punxsutawney Phil in reverse, marveling at your mostly-missing shadow.
Do We All See the Same Part of the Moon?
almanac.com/do-we-all-see-same-moon
How The Sky Changes as You Travel
Since I’m on vacation, I’m reminded each evening about how different the sky gets when you travel. Take Boston to Hawaii. Yes, the Moon will appear differently. Got friends and family in different locations? Planning travel? Let’s explore whether we all see the Moon and Sun in the same way.
Actually, changing your longitude, your east-west location, alters nothing. It’s going south or north that creates strangeness. So going from New York to Rome won’t change the sky. But Minneapolis to Miami or Alaska to Arizona is a different story.
The Sunset and Moonset
You see it with your first sunset. From Europe, Canada, or the northern three quarters of the U.S., it takes the Moon three minutes to move its own width as it sets, and the same timeframe applies to the Sun since it’s the same apparent size. Both of those disks require three minutes to completely pass through the horizon, because both of them always glide into the western horizon diagonally.
But from the tropics, which includes Hawaii, the Sun and Moon each drop straight down like cannon balls, creating the world’s fastest sunsets. This near-vertical downward motion also explains why twilight is shortest when you vacation closer to the equator.
Do Different Places See the Moon Differently?
It depends on what you mean.
Yes, we all see the same phases of the Moon from Earth, no matter where we live in the world. This is because Moon phases (how much of the disk is illuminated) is caused by the positions of the Sun, Moon, and Earth. See your Moon Phase.
However, the Moon does not look the same because we observe the Moon from different angles on Earth. In the Northern Hemisphere, the illuminated part of the Moon travels from right to left; in the southern hemisphere, the sunlit part seem to travel from left to right. Again, this all depends on traveling north or south, i.e., your latitude, not your east-west longitude.
On the left, see the waning crescent Moon phase from the Northern Hemisphere. On the right, see the same Moon phase from the Southern Hemisphere. It appears upside down!
Also, from the tropics, you’ll sometimes see the Moon straight overhead, which never happens from Europe, Canada, or the U.S. Expect that zenith Moon to happen at midnight when it’s full, and during sunset when it’s a first quarter half-Moon.
Seeing the Green Flash at Sunset
I traveled to Thailand for my vacation. If you travel to any tropical location, such as Hawaii, this offers the increased chances to see sunset’s fabled Green Flash. Not that it’s necessarily hidden elsewhere. Californians with cliffside homes facing the Pacific have the one necessary requirement every evening—a perfectly unblocked horizon. But vacationers in the tropics are certainly more likely than, say, Vermonters to not have sunset obscured by hills or trees.
Here’s how you see a green flash:
-Enjoy a lot of sunsets! You need to be able to see below the real horizon, for example across water. If it’s a cloudless day, with steady temperatures, the final tiny dot of the setting Sun that appears orange will suddenly turn a lovely emerald green, just for one to four seconds, and then it too will set. (Do not ever stare right at the sun; look just after the sun is below the horizon.)
Here’s what happens:
-When you look at the setting Sun or anything at the horizon, you’re looking through 40 times more air than when you’re looking overhead. This exaggerates air’s tendency to bend each color of sunlight at a slightly different angle. So, a setting Sun is actually a series of differently colored Sun images setting one after the other. The red Sun sets first, followed immediately by the orange Sun, then yellow. Green is the last to go, because the Sun’s blue image has been thoroughly dispersed and scattered away by the long path to your eyes.
How often does this happen? I’ve carefully watched for the green flash every time conditions were right, and saw it around 25 times. I’d looked for it over 200 times, so if my experience is typical, it would seem to appear about 10% of the time.
All these travellers’ sky effects require no equipment, charts, or even unpolluted rural skies. They’re there reliably. You just have to get out of town. Which, at this time of year, usually means to the south!
