Wyoming got more than 15 hours of daylight on June 21, the summer solstice.
It’s lost nearly 10 seconds of daylight since then, and it’ll keep getting darker, earlier and later, until Christmas.
Over the next three months, Wyoming will start losing daylight at an increasingly fast pace. What starts as a few seconds on June 22 will be several minutes by late September.
It won’t stop until the winter solstice on Dec. 21. There’s still plenty of long summer nights ahead, but the days are already getting shorter.
“It’s not that noticeable now, but we’ll be losing two minutes per day by the end of July,” said Max Gilbraith, planetarium coordinator at the University of Wyoming. “The sun’s going to be at a slightly lower angle every day until Dec. 21, and then it starts all over again."
To The Minute
The summer solstice is the longest day of the year, but in Wyoming the exact moment of the solstice occurred at 2:44 a.m. June 21.
“That’s technically when the sun is directly over the Tropic of Cancer,” Gilbraith said. “It’s the instantaneous moment where the Earth's Northern Hemisphere is maximally tilted toward the sun.”
That doesn’t make the longest day of the year any longer, but figuring out the exact timing of these events is something many civilizations have attempted to discover for thousands of years.
“The Medicine Wheel in Bighorn National Forest was designed to get the exact dates of the solstices correct,” Gilbraith said. “That’s a Wyoming connection to astronomy and the summer solstice that goes back over 1,500 years.”
Gilbraith added that our concept of time can be traced to “the first civilization.”
“The Babylonians developed the 60-counting system based on the 360 degrees of a circle, which is very close to the 365 days in a year,” he said.
Most Wyomingites aren’t aware of this astrological significance in human history. What they know is that Wyoming got a lot of glorious daylight that Sunday.
The longest day of the year was longer depending on where you were in Wyoming.
Laramie, in southern Wyoming, got 15 hours, nine minutes, and 43 seconds of daylight June 21. Meanwhile, Ranchester got 15 hours, 36 minutes, and 18 seconds of daylight on the same day.
“That’s almost an extra 30 minutes from southern to northern Wyoming,” Gilbraith said.
Since then, the Earth’s tilt has been gradually shifting as it continues its orbit the sun. That’s why the seconds have started to slowly slip away.
Still Sun
“Solstice” is derived from the Latin phrase “still sun.” According to Gilbraith, the sun appears to stay in the same spot during the summer and winter solstices.
“The sun appears to rise, set and hang out in the same spot in the sky for several days,” he said. “It does move during those days, but it’s not that noticeable. That’s why we’ve only lost a few seconds in the last two days.”
The loss of daylight won’t be noticeable for several weeks. After all, how noticeable is a 20-second loss of daylight per day in late June?
The further we get from the summer solstice, the more daylight is lost. It’ll happen sooner than many realize.
A 15-hour day at the beginning of July will be around 14 hours and 23 minutes by the end of July. That's when the losses really start to add up, as much as two minutes a day going into August.
"If you lose two minutes a day every day for a month, that's an hour of daylight lost,' Gilbraith said. "And the amount of daylight lost per day will only increase from there."
By the winter solstice, Wyoming’s shortest day will have around nine hours and 12 minutes of daylight in Laramie. Ranchester, meanwhile, will have around eight hours and 27 minutes of daylight.
“We’re physically closer to the sun in the Northern Hemisphere during winter," Gilbraith said. "It's the length of day and the angle of the sun that causes the seasons.”
Later Sunrise Or Earlier Sunset?
When Wyoming loses daylight, do sunrises get later, or do sunsets get earlier?
It’s both, according to Gilbraith, as the loss of daylight impacts both ends of the day evenly.
“I think most people's perception is that that afternoon is getting darker earlier,” he said. “The sunset is changing, but so is the sunrise. It’s not just one.”
However, the elephant in the room is an arbitrary difference that’s been in place for more than a century: Daylight Saving Time.
“The length of the day is always changing, but it’d be easier to track without Daylight Saving Time,” Gilbraith said. “It started as ‘War Time’ in World War I because they wanted to save electricity for factories. So, they moved the clock up so people would use less light in the evenings.”
Many people continue to advocate for the United States to adopt permanent Daylight Saving Time or abolish it altogether in favor of permanent Standard Time. Nothing’s come of it yet, at least not in an actionable way.
Wyoming is ready to adopt permanent Daylight Saving Time. The Wyoming Legislature passed a trigger bill in 2020, but it only takes effect if the federal government passes similar legislation.
The federal government has been unable and hasn’t tried since 2018.
Those "Long" Summer Nights
Nobody likes the idea of the slow but inevitable loss of sunlight that’s already started, but it doesn’t happen overnight. That’s why the equinoxes are significant.
Equinox is another Latin-derived term for “equal night.” It’s the two points of the year, in April and September, when the sun is directly over the equator.
It’s also when Wyoming loses or gains the most daylight, depending on the season. On the September equinox, Gilbraith said we’ll lose nearly 3 minutes of sunlight each day.
“The rising and setting position in the sun is slowest close to the solstices and fastest near the equinoxes," he said. "It peaks around 2 minutes, 43 seconds per day at the September equinox."
As we draw closer the September equinox, the amount of daylight lost each day will slowly increase every day. However, there's still plenty of time to enjoy the summer sun.
“Days will remain longer than nights until September 20,” Gilbraith said. “As much as it's all downhill from here, we still have to look forward to December. Our ancestors built Stonehenge to remind themselves that the daylight comes back.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
