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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Paul Saffo
Date: 2024 Jun 20, 08:30 -0700
I tend to wince at these attempts to oversell routine celestial events (cue "super moon, named moons, etc) to the public, but this one actually does a nice job of explaining what a solstice is, day length, seasons, etc. And (gasp!) even mentions calendar corrections and includes numbers and tables! Definitely worth looking at it on the web to see the table and pics.
-p
https://www.washingtonpost.com/weather/2024/06/19/summer-solstice-longest-day-earliest/
Summer solstice 2024: Season to have its earliest start since 1796
The summer solstice, marking the year’s longest daylight period, officially occurs Thursday at 4:51 p.m. Eastern time. Here’s why it’s a day early.
By Justin Grieser
Updated June 20, 2024 at 9:21 a.m. EDT|Published June 19, 2024 at 6:00 a.m. EDT
Summer is arriving a bit earlier than usual this year, and not just because a major heat wave is baking the eastern United States and Canada this week. Thursday’s summer solstice — the longest day and shortest night of the year in the Northern Hemisphere — is the earliest in 228 years, since 1796, when George Washington was president.
The 2024 summer solstice arrives June 20 at 4:51 p.m. Eastern time, according to the U.S. Naval Observatory. A day later, on June 21, the full moon will rise at 9:08 p.m. Eastern. The “strawberry moon” is the lowest full moon of the year, staying close to the horizon as the sun soars to its highest point in the sky.
What exactly happens on the solstice?
In most years, the summer solstice occurs on June 21. That’s when Earth’s North Pole reaches its maximum tilt toward the sun, and the sun appears at its northernmost point directly over the Tropic of Cancer, 23.5 degrees north of Earth’s equator. In the Northern Hemisphere, the sun takes its longest and highest path through the sky, which is why we experience our longest daylight hours and shortest night of the year.
Daylight hours on the summer solstice depend on latitude: The closer you move toward the North Pole, the more time the sun spends above the horizon. The sun is up for 16 hours in Seattle, but only 13 hours and 45 minutes in Miami.
Washington, D.C., sees about 14 hours 54 minutes of daylight on the summer solstice, with sunrise at 5:42 a.m. and sunset at 8:36 p.m., according to timeanddate.com.
Two ways to observe the solstice directly are by watching your shadow as well as the location of sunrise and sunset. The high arc of the sun means you will cast your shortest midday shadow of the year on the summer solstice. You will also see the sun rise and set at its northernmost points along the horizon.
Why is the solstice early this year?
The main reason for the early solstice is that human calendars aren’t perfect. While a normal year (or non-leap year) has 365 days, Earth’s orbit around the sun each year is not exactly that long. On average, it takes about 365 days, 5 hours and 49 minutes — or 365.24219 days, according to timeanddate.com. To account for that extra quarter-day, the Gregorian calendar we adopted in the late 16th century adds one extra day (Feb. 29) to the calendar every four years. This is why we have leap years that are 366 days long.
During leap years such as 2024, the solstices and equinoxes occur about 18 hours and 11 minutes earlier than the previous year. Then, during successive non-leap years, the seasons begin 0.24219 days later than the previous year (approximately 5 hours and 49 minutes).
Over time, this means that the solstices and equinoxes drift earlier [see linked article]
